Saturday, 29 December 2007

Half a million year old tibia!

The site where Britain's oldest man was discovered will be preserved so archaeologists can see if it holds any more secrets.
There was interest from around the world nine years ago when the shin bone of a man, dating back 500,000 years, was unearthed at Boxgrove near Chichester.
The land has been safeguarded thanks to a £100,000 grant to English Heritage, which now has site ownership.
It is planning to restore the 20-acre site and excavate the section it is believed was a water hole used by early man and animals, including rhinocerous and bison.
Archaeologists hope to uncover more clues about how the man, dubbed Boxgrove Man, lived.
Mark Roberts, principal research fellow at the University College London Institute of Archaeology, led the team which made the first discovery.
Speaking at the quarry yesterday, he said: "With the approval of West Sussex County Council we hope to start a restoration programme this summer.
"This will entail securing the site and clearing it of scrub, reducing some of the sheer slopes of the quarry and partially back-filling the central area, using only existing material.
"Further research excavations, which are likely to reveal more astonishing finds, can then take place."
Andy Brown, assistant regional director of English Heritage, said: "There are decades of excavation at this site.
"It may take 100 or even 200 years to exhaust all the information.
"This is a very important day for us. For a decade this site has been revealed to be of superb archaeological importance, not just in the UK but also in north-west Europe.
"By buying this site it means we can protect it in a way that would not have been possible under normal circumstances due to a quirk in the legislation under which we operate."
Carbon dating showed the human shin bone, unearthed in 1993, belonged to a 6ft active man. He survived on a diet of raw meat in an area of cliff face between Arundel and Portsdown Hill in Hampshire, with the land below stretching to Northern France.
Archaeologists also uncovered two teeth around a metre deeper than the shin bone. and primitive tools made from flint and antler horns.
But despite further searches they failed to uncover the most treasured prize - Boxgrove Man's skull.
Now they hope to find what they describe as the "Holy Grail" of the site.
Archive Home
From the archivehttp://www.theargus.co.uk© Newsquest Media Group 2003

Image: Natural History Museum, London.

Why Pregnant Women Don't Tip Over




According to anthropologists, the human adaptation is unique among primates and may have arisen shortly after early humans started walking upright.

"Bipedalism challenges stable postures, because the abdomen expands in front of the body as the baby grows," said Katherine Whitcome, an anthropologist at Harvard University.

"This changes the mother's center of mass, which is a critical point in any three-dimensional body on which gravity acts."

As this center of mass shifts forward, pregnant women have to lean back and change their gait to stay steady.

Wedge-shaped vertebrae in the lower back might be the key evolutionary adaptation that helps human females maintain a stable posture over the course of pregnancy. This realigns the center of mass over the hips, knees, and ankles to correct the imbalance—but it creates another problem.

"It generates loading on parts of the vertebral column that are not normally under such stress," Whitcome said.

Joint Support

To find out how pregnant women keep their balance without damaging their spines, Whitcome and her colleagues studied 19 pregnant females between the ages of 20 and 40.

The team found that the key appears to be joints in the bony vertebrae that wrap protectively around the spinal cord.
These joints become heavily loaded whenever people lean back.

But the size of the joints relative to the vertebrae in the lower back is much larger in women than in men. This suggests that the joints' larger surface area is an adaptation to bear more load.
And the shape of the vertebrae in women tapers off toward the back, creating a wedge shape that further facilitates arching, Whitcome said.

Women also have three such vertebrae, while men have just two.

"These wedge-shaped vertebrae, when stacked together, form a natural curve and help reduce the shearing stress generated during pregnancy," said Whitcome, whose findings appear today in the journal Nature.

Evolutionary Adaptation

Whitcome and her colleagues suggest that the special vertebrae are unique evolutionary adaptations that helped the first ancestors of human women as they started walking upright.

For example, the researchers have found the unusual spinal characteristics in lumbar vertebral columns from Australopithecus africanus fossils dating back nearly two million years (related feature: atlas of human evolution).

"The female characteristics, which are explained by the biomechanics of fetal load, are present in the fossil record, suggesting that these adaptations evolved very early in humans," Whitcome noted.

Karen Rosenberg is an anthropologist at the University of Delaware who was not involved in the new study.

She said that the feature would have been naturally selected in humans at about the same time that bipedalism evolved, nearly five million years ago.

And John Fleagle, an anthropologist at Stony Brook University, commented that "there are lots of neat things about this paper."

"It documents some striking features of the lumbar spine of female humans that seem rather clearly related to the demands of pregnancy."

Scientists had previously known about male-female differences in the shape of the pelvis related to birthing, Fleagle added. But spinal differences between males and females had not been appreciated until now.

"Like so many discoveries," he added, "this is one that causes you to slap your forehead and exclaim, Of course! Why hasn't anyone thought of this before?"
Source:Amitabh Avasthi
for National Geographic News
December 12, 2007

Wednesday, 26 December 2007

Evolution tied to Earth movement




Scientists long have focused on how climate and vegetation allowed human ancestors to evolve in Africa. Now, University of Utah geologists are calling renewed attention to the idea that ground movements formed mountains and valleys, creating environments that favored the emergence of humanity.

“Tectonics [movement of Earth’s crust] was ultimately responsible for the evolution of humankind,” Royhan and Nahid Gani of the university’s Energy and Geoscience Institute write in the January, 2008, issue of Geotimes, published by the American Geological Institute.

They argue that the accelerated uplift of mountains and highlands stretching from Ethiopia to South Africa blocked much ocean moisture, converting lush tropical forests into an arid patchwork of woodlands and savannah grasslands that gradually favored human ancestors who came down from the trees and started walking on two feet – an energy-efficient way to search larger areas for food in an arid environment.

In their Geotimes article, the Ganis – a husband-and-wife research team who met in college in their native Bangladesh – describe this 3,700-mile-long stretch of highlands and mountains as “the Wall of Africa.” It parallels the famed East African Rift valley, where many fossils of human ancestors were found.

“Because of the crustal movement or tectonism in East Africa, the landscape drastically changed over the last 7 million years,” says Royhan Gani (pronounced rye-hawn Go-knee), a research assistant professor of civil and environmental engineering. “That landscape controlled climate on a local to regional scale. That climate change spurred human ancestors to evolve from apes.”

Hominins – the new scientific word for humans (Homo) and their ancestors (including Ardipithecus, Paranthropus and Australopithecus) – split from apes on the evolutionary tree roughly 7 million to 4 million years ago. Royhan Gani says the earliest undisputed hominin was Ardipithecus ramidus 4.4 million years ago. The earliest Homo arose 2.5 million years ago, and our species, Homo sapiens, almost 200,000 years ago.

Tectonics – movements of Earth’s crust, including its ever-shifting tectonic plates and the creation of mountains, valleys and ocean basins – has been discussed since at least 1983 as an influence on human evolution.

But Royhan Gani says much previous discussion of how climate affected human evolution involves global climate changes, such as those caused by cyclic changes in Earth’s orbit around the sun, and not local and regional climate changes caused by East Africa’s rising landscape.


A Force from within the Earth

The geological or tectonic forces shaping Africa begin deep in the Earth, where a “superplume” of hot and molten rock has swelled upward for at least the past 45 million years. This superplume and its branching smaller plumes help push apart the African and Arabian tectonic plates of Earth’s crust, forming the Red Sea, Gulf of Aden and the Great Rift Valley that stretches from Syria to southern Africa.

As part of this process, Africa is being split apart along the East African Rift, a valley bounded by elevated “shoulders” a few tens of miles wide and sitting atop “domes” a few hundreds of miles wide and caused by upward bulging of the plume.

The East African Rift runs about 3,700 miles from the Ethiopian Plateau south-southwest to South Africa’s Karoo Plateau. It is up to 370 miles wide and includes mountains reaching a maximum elevation of about 19,340 feet at Mount Kilimanjaro.

The rift “is characterized by volcanic peaks, plateaus, valleys and large basins and freshwater lakes,” including sites where many fossils of early humans and their ancestors have been found, says Nahid Gani (pronounced nah-heed go-knee), a research scientist. There was some uplift in East Africa as early as 40 million years ago, but “most of these topographic features developed between 7 million and 2 million years ago.”

A Wall Rises and New Species Evolve.

“Although the Wall of Africa started to form around 30 million years ago, recent studies show most of the uplift occurred between 7 million and 2 million years ago, just about when hominins split off from African apes, developed bipedalism and evolved bigger brains,” the Ganis write.

“Nature built this wall, and then humans could evolve, walk tall and think big,” says Royhan Gani. “Is there any characteristic feature of the wall that drove human evolution?”

The answer, he believes, is the variable landscape and vegetation resulting from uplift of the Wall of Africa, which created “a topographic barrier to moisture, mostly from the Indian Ocean” and dried the climate. He says that contrary to those who cite global climate cycles, the climate changes in East Africa were local and resulted from the uplift of different parts of the wall at different times.

Royhan Gani says the change from forests to a patchwork of woodland and open savannah did not happen everywhere in East Africa at the same time, and the changes also happened in East Africa later than elsewhere in the world.

The Ganis studied the roughly 300-mile-by-300-mile Ethiopian Plateau – the most prominent part of the Wall of Africa. Previous research indicated the plateau reached its present average elevation of 8,200 feet 25 million years ago. The Ganis analyzed rates at which the Blue Nile River cut down into the Ethiopian Plateau, creating a canyon that rivals North America’s Grand Canyon. They released those findings in the September 2007 issue of GSA Today, published by the Geological Society of America.

The conclusion: There were periods of low-to-moderate incision and uplift between 29 million and 10 million years ago, and again between 10 million and 6 million years ago, but the most rapid uplift of the Ethiopian Plateau (by some 3,200 vertical feet) happened 6 million to 3 million years ago.

The Geotimes paper says other research has shown the Kenyan part of the wall rose mostly between 7 million and 2 million years ago, mountains in Tanganyika and Malawi were uplifted mainly between 5 million and 2 million years ago, and the wall’s southernmost end gained most of its elevation during the past 5 million years.

“Clearly, the Wall of Africa grew to be a prominent elevated feature over the last 7 million years, thereby playing a prominent role in East African aridification by wringing moisture out of monsoonal air moving across the region,” the Ganis write. That period coincides with evolution of human ancestors in the area.

Royhan Gani says the earliest undisputed evidence of true bipedalism (as opposed to knuckle-dragging by apes) is 4.1 million years ago in Australopithecus anamensis, but some believe the trait existed as early as 6 million to 7 million years ago.

The Ganis speculate that the shaping of varied landscapes by tectonic forces – lake basins, valleys, mountains, grasslands, woodlands – “could also be responsible, at a later stage, for hominins developing a bigger brain as a way to cope with these extremely variable and changing landscapes” in which they had to find food and survive predators.

For now, Royhan Gani acknowledges the lack of more precise timeframes makes it difficult to link specific tectonic events to the development of upright walking, bigger brains and other key steps in human evolution.

“But it all happened within the right time period,” he says. “Now we need to nail it down.”

Are humans evolving faster?

Findings suggest we are becoming more different, not alike.
Researchers discovered genetic evidence that human evolution is speeding up – and has not halted or proceeded at a constant rate, as had been thought – indicating that humans on different continents are becoming increasingly different.

“We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago,” says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the National Academy of Sciences:

-- “We aren’t the same as people even 1,000 or 2,000 years ago,” he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. “The dogma has been these are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influence.”

-- “Human races are evolving away from each other,” Harpending says. “Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed humanity.” He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, “and there has not been much flow of genes between the regions since then.”

“Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing relatively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups.”

The increase in human population from millions to billions in the last 10,000 years accelerated the rate of evolution because “we were in new environments to which we needed to adapt,” Harpending adds. “And with a larger population, more mutations occurred.”

Study co-author Gregory M. Cochran says: “History looks more and more like a science fiction novel in which mutants repeatedly arose and displaced normal humans – sometimes quietly, by surviving starvation and disease better, sometimes as a conquering horde. And we are those mutants.”

Harpending conducted the study with Cochran, a New Mexico physicist, self-taught evolutionary biologist and adjunct professor of anthropology at the University of Utah; anthropologist John Hawks, a former Utah postdoctoral researcher now at the University of Wisconsin, Madison; geneticist Eric Wang of Affymetrix, Inc. in Santa Clara, Calif.; and biochemist Robert Moyzis of the University of California, Irvine.

No Justification for Discrimination

The new study comes from two of the same University of Utah scientists – Harpending and Cochran – who created a stir in 2005 when they published a study arguing that above-average intelligence in Ashkenazi Jews – those of northern European heritage – resulted from natural selection in medieval Europe, where they were pressured into jobs as financiers, traders, managers and tax collectors. Those who were smarter succeeded, grew wealthy and had bigger families to pass on their genes. Yet that intelligence also is linked to genetic diseases such as Tay-Sachs and Gaucher in Jews.

That study and others dealing with genetic differences among humans – whose DNA is more than 99 percent identical – generated fears such research will undermine the principle of human equality and justify racism and discrimination. Other critics question the quality of the science and argue culture plays a bigger role than genetics.

Harpending says genetic differences among different human populations “cannot be used to justify discrimination. Rights in the Constitution aren’t predicated on utter equality. People have rights and should have opportunities whatever their group.”

Analyzing SNPs of Evolutionary Acceleration

The study looked for genetic evidence of natural selection – the evolution of favorable gene mutations – during the past 80,000 years by analyzing DNA from 270 individuals in the International HapMap Project, an effort to identify variations in human genes that cause disease and can serve as targets for new medicines.

The new study looked specifically at genetic variations called “single nucleotide polymorphisms,” or SNPs (pronounced “snips”) which are single-point mutations in chromosomes that are spreading through a significant proportion of the population.

Imagine walking along two chromosomes – the same chromosome from two different people. Chromosomes are made of DNA, a twisting, ladder-like structure in which each rung is made of a “base pair” of amino acids, either G-C or A-T. Harpending says that about every 1,000 base pairs, there will be a difference between the two chromosomes. That is known as a SNP.

Data examined in the study included 3.9 million SNPs from the 270 people in four populations: Han Chinese, Japanese, Africa’s Yoruba tribe and northern Europeans, represented largely by data from Utah Mormons, says Harpending.

Over time, chromosomes randomly break and recombine to create new versions or variants of the chromosome. “If a favorable mutation appears, then the number of copies of that chromosome will increase rapidly” in the population because people with the mutation are more likely to survive and reproduce, Harpending says.

“And if it increases rapidly, it becomes common in the population in a short time,” he adds.

The researchers took advantage of that to determine if genes on chromosomes had evolved recently. Humans have 23 pairs of chromosomes, with each parent providing one copy of each of the 23. If the same chromosome from numerous people has a segment with an identical pattern of SNPs, that indicates that segment of the chromosome has not broken up and recombined recently.

That means a gene on that segment of chromosome must have evolved recently and fast; if it had evolved long ago, the chromosome would have broken and recombined.

Harpending and colleagues used a computer to scan the data for chromosome segments that had identical SNP patterns and thus had not broken and recombined, meaning they evolved recently. They also calculated how recently the genes evolved.

A key finding: 7 percent of human genes are undergoing rapid, recent evolution.

The researchers built a case that human evolution has accelerated by comparing genetic data with what the data should look like if human evolution had been constant:


The study found much more genetic diversity in the SNPs than would be expected if human evolution had remained constant.


If the rate at which new genes evolve in Africans was extrapolated back to 6 million years ago when humans and chimpanzees diverged, the genetic difference between modern chimps and humans would be 160 times greater than it really is. So the evolution rate of Africans represents a recent speedup in evolution.


If evolution had been fast and constant for a long time, there should be many recently evolved genes that have spread to everyone. Yet, the study revealed many genes still becoming more frequent in the population, indicating a recent evolutionary speedup.

Next, the researchers examined the history of human population size on each continent. They found that mutation patterns seen in the genome data were consistent with the hypothesis that evolution is faster in larger populations.

Evolutionary Change and Human History: Got Milk?

“Rapid population growth has been coupled with vast changes in cultures and ecology, creating new opportunities for adaptation,” the study says. “The past 10,000 years have seen rapid skeletal and dental evolution in human populations, as well as the appearance of many new genetic responses to diet and disease.”

The researchers note that human migrations into new Eurasian environments created selective pressures favoring less skin pigmentation (so more sunlight could be absorbed by skin to make vitamin D), adaptation to cold weather and dietary changes.

Because human population grew from several million at the end of the Ice Age to 6 billion now, more favored new genes have emerged and evolution has speeded up, both globally and among continental groups of people, Harpending says.

"We have to understand genetic change in order to understand history,” he adds.

For example, in China and most of Africa, few people can digest fresh milk into adulthood. Yet in Sweden and Denmark, the gene that makes the milk-digesting enzyme lactase remains active, so “almost everyone can drink fresh milk,” explaining why dairying is more common in Europe than in the Mediterranean and Africa, Harpending says.

He now is studying if the mutation that allowed lactose tolerance spurred some of history’s great population expansions, including when speakers of Indo-European languages settled all the way from northwest India and central Asia through Persia and across Europe 4,000 to 5,000 years ago. He suspects milk drinking gave lactose-tolerant Indo-European speakers more energy, allowing them to conquer a large area.

But Harpending believes the speedup in human evolution “is a temporary state of affairs because of our new environments since the dispersal of modern humans 40,000 years ago and especially since the invention of agriculture 12,000 years ago. That changed our diet and changed our social systems. If you suddenly take hunter-gatherers and give them a diet of corn, they frequently get diabetes. We’re still adapting to that. Several new genes we see spreading through the population are involved with helping us prosper with high-carbohydrate diet.”



University of Utah Public Relations
Eurekalert December 2007.

Sunday, 23 December 2007

Ancient "Salt Cured" Man Found in Iranian Mine





Scientists believe the man was a Roman Empire-era salt mine worker killed by falling rocks during an earthquake.

Scientific Treasure Trove

Five other "salt men" have been found in the mine in recent years. They range in date from the Achaemenid period (539 to 333 B.C.) to the Sasanian era (A.D. 240 to 640The salt men have proven to be scientific treasure troves, due to their advanced state of preservation. For instance, their beards, hair and garments have remained largely intact over time. Some still had food in their stomach.

Kelly Hearn
for National Geographic News

July 3, 2007

Morphological changes in the shape of the non-pathological bony knee joint with age:

a morphometric analysis of the distal femur and proximal tibia in three populations of known age at death

This study examines possible morphological variation in the knee joint of Homo sapiens with increasing age in ostensively healthy and non-pathological distal femora and proximal tibiae. Throughout the lifetime of each individual, the hard tissue of the knee undergoes considerable remodelling as a response to biomechanical stresses, changes in bone microarchitecture and reduction of bone mineral content as a concomitant of ageing. The knee is also subject to greater levels of degenerative joint disease than any other joint. If death occurs whilst such diseases are in the earliest stages, initial bone changes may not be visually obvious in museum specimens. If such specimens are used for comparative analyses, it is hypothesised that changes might render it problematic if all ages are conglomerated into discrete samples. This study therefore investigates the degree to which the distal femur and proximal tibia change shape during ageing and, if changes are present, whether they are expressed similarly in males and females. It also examines whether changes are of greater magnitude than those morphological differences which might exist between populations. In an example population of African-Americans, results indicate that there is a statistically significant difference in shape between age groups and those differences become progressively greater between the youngest and oldest adults. Results also show that although morphological variation caused by ageing is apparent, those shape differences attributable to sexual dimorphism are more powerful. When two additional populations are analysed jointly with the African-Americans (Caucasian Americans and the European Spitalfields sample), results indicate that inter-population shape differences are considerably greater than differences caused by increasing age. Results imply that it is justifiable to combine specimens of all ages into discrete samples for comparative purposes. Copyright © 2007 John Wiley & Sons, Ltd.

21 December 2007, 07:07:00 S. D. Stevens, U. Strand Vi[dstrok]arsdóttir

Monday, 19 November 2007

Footprint of Roman soldier's sandal discovered at Hippos


Archaeologists have discovered a footprint made by the sandal of a Roman soldier in a wall surrounding the Hellenistic-Roman city of Hippos (Sussita), east of the Sea of Galilee. The footprint was discovered during this eighth season of excavation, led by Prof. Arthur Segal from the Zinman Institute of Archaeology at the University of Haifa in conjunction with archaeologists from the Polish Academy of Sciences and Concordia University in St. Paul, Minnesota. "This rare footprint, which is complete and well preserved, hints at who built the walls, how and when," said Michael Eisenberg of the Zinman Institute at the University of Haifa.

The print, made by a hobnailed sandal called caliga, the sandal worn by Roman soldiers, is one of the only finds of this type. The discovery of the print in the cement led archaeologists to presume that legionnaires participated in construction of the walls.
The excavations of this section of the southern city walls also revealed towers and well-protected structures for positioning weapons such as catapults and ballistae built into the wall.

The ancient city of Hippos (Sussita), at 350 meters above sea level, overlooks the Sea of Galilee. The city was established during the period of Seleucid rule. It flourished during the Roman and Byzantine periods until it was destroyed by an earthquake in the year 749. Hippos (Sussita), together with Beit Shean and other cities east of the Jordan River, formed the "Decapolis", the area in which Jesus performed most of the miracles described in the New Testament. "The remains of Sussita, its view of the Golan Heights and the Galilee and its historic significance in Christianity, have made it one of the most attractive sites in northern Israel," said Prof. Segal.

This season's excavations have uncovered additional, important finds: the city's colonnaded street, some 240 meters long; a magnificent, marble-paneled bathhouse; and a glass bottle with an embossed face. On the final day of the dig another unusual find was uncovered: part of a white marble statue, a hand holding a staff, apparently part of a Greek god. The archaeologists are hopeful that during the next digging season they will find other pieces of the statue which is estimated to be 2 meters high.


Source:EurekAlert!26-Aug-2007

Human ancestors more primitive that once thought:lower limb morphology-long legs and an arched foot

A team of researchers, including Herman Pontzer, Ph.D., assistant professor of physical anthropology in Arts & Sciences, has determined through analysis of the earliest known hominid fossils outside of Africa, recently discovered in Dmanisi, Georgia, the former Soviet republic, that the first human ancestors to inhabit Eurasia were more primitive than previously thought.

The fossils, dated to 1.8 million years old, show some modern aspects of lower limb morphology, such as long legs and an arched foot, but retain some primitive aspects of morphology in the shoulder and foot. The species had a small stature and brain size more similar to earlier species found in Africa.

"Thus, the earliest known hominins to have lived outside Africa in temperate zones of Eurasia did not yet display the full set of derived skeletal features," the researchers conclude.

The findings, published Sept. 20 in the journal "Nature," are a marked step in learning more about the first human ancestors to migrate from Africa.

The lead author of the paper is David Lordpkipanidze, director of the National Museum of Georgia. Collaborators on the study include Pontzer and researchers from Georgia, Switzerland, Italy and Spain.

The new evidence shows how this species had the anatomical and behavioral capacity to be successful across a range of environments and expand out of Africa, said Pontzer, who studies how the musculoskeletal anatomy of an animal reflect its performance, ecological niche and evolutionary history.

"This research tells us that the limb proportions and behavioral flexibility which allowed this species to expand out of Africa were there at least 1.8 million years ago," Pontzer said.

Dmanisi is the site of a medieval village located about 53 miles southwest of Tbilisi, Georgia on a promontory at the confluence of the Mashavera and Phinezauri rivers. Archaeological exploration of the ruins began in the 1930s, but systematic excavations were not undertaken until the 1980s. Pontzer has been studying the site for more than six years.


Source:EurekAlert!20-Sep-2007

Monday, 29 October 2007

‘Mint’ Pain Killer Takes Leaf out of Ancient Medical Texts

A new treatment inspired by ancient Greek and Chinese remedies could offer pain relief to millions of patients with arthritis and nerve damage, a new study by The University of Edinburgh suggests.
The Greek scholar Hippocrates treated sprains, joint pains and inflammation by cooling the skin, and traditional Chinese remedies used mint oil to the same end.
Now University researchers have discovered that cooling chemicals which have the same properties as mint oil have a dramatic pain–killing effect when applied in small doses to the skin.
Unlike conventional pain killers, these compounds are likely to have minimal toxic side effects, especially because they are applied externally to the skin. This should mean they are ideal for chronic pain patients for whom conventional pain killers often do not work.
The study explains that the ‘mint oil’ and related chemical compounds act through a recently discovered receptor (a protein which is capable of binding with these chemicals) which is found in a small percentage of nerve cells in the human skin.
"Our discovery means that patients can be given low doses of a powerful pain killer, delivered through the skin, without side effects."Professor Susan Fleetwood-Walker.
When this receptor, called TRPM8, is activated by the cooling chemicals or cool temperatures, it inhibits the ‘pain messages’ being sent from the locality of the pain to the brain.
Thus, the new treatment makes good use of the body’s own mechanisms for killing pain.
Professor Susan Fleetwood-Walker, who jointly led the study with Dr Rory Mitchell, says:
“Our discovery means that patients can be given low doses of a powerful pain killer, delivered through the skin, without side effects. We hope clinical trials on the compounds will begin within the year.
“This discovery of the pain-relieving properties of mint oil and related compounds has great potential for alleviating the suffering of millions of chronic pain patients, including those with arthritis or those who have had nerve damage or spinal injury following major accidents. Conventional painkillers such as morphine are often ineffective in cases of chronic pain, and simply lowering the temperature of the skin is too inexact.”
The findings would doubtless have been of interest to Hippocrates, the founding father of modern medicine. Writing in the fifth century BC, in chapter 5 of his classic text, Aphorisms, he stated:
“Swellings and pains in the joints, ulceration, those of a gouty nature, and sprains, are generally improved by a copious affusion of cold water, which reduces the swelling, and removes the pain; for a moderate degree of numbness removes pain.”


The research has been funded by the Wellcome Trust and the Medical Research Council, and its findings appear in the journal, Current Biology.
Resource:University of Edinburgh

Ancient clay remedies-possible new area for podiatric research?

U.S. scientists are investigating the efficacy of a French clay that
was used for thousands of years to kill several kinds of
disease-causing bacteria. "There are very compelling reports of clay
treating infections, but that's anecdotal evidence, not science,"
said Arizona State University-Tempe Associate Research Professor
Lynda Williams. Williams and Assistant Professor Shelley Haydel are
coordinating three teams of U.S. researchers - from ASU, the U.S.
Geological Survey and the State University of New York-Buffalo -
under a two-year, $440,000 grant from the National Center for
Complementary and Alternative Medicine.
Williams said people for thousands of years used clay to heal
wounds, soothe indigestion, and kill intestinal worms. Although the
practice has declined today, the recent increase in drug-resistant
bacteria has prompted scientists to look at the ancient remedies to
determine their efficacy. "We're beginning to generate the first
scientific evidence of why some minerals might kill bacterial
organisms and others might not," said Williams.

Source: News Daily, United Press International (October 2007)

Friday, 26 October 2007

Patients should ask surgeons about using honey to heal wounds

Surgeons are being advised to consider the supermarket as well as the drugs cupboard when it comes to effective wound healing, according to a research review published in the October issue of IJCP, the International Journal of Clinical Practice.
And patients who’ve undergone surgery should ask their doctors whether they should apply honey to their wounds to speed up healing and reduce infection.
“Honey is one of the oldest foods in existence and was an ancient remedy for wound healing” explains lead author Dr Fasal Rauf Khan from North West Wales NHS Trust in Bangor. “It was found in the tomb of King Tutankhamun and was still edible as it never spoils.”
Honey is enjoying a revival as more reports of its effectiveness are published, he adds.
“Researchers started to document the wound healing properties of honey in the early 20th century, but the introduction of antibiotics in 1940 temporarily halted its use.
“Now concerns about antibiotic resistance, and a renewed interest in natural remedies, has prompted a resurgence in the antimicrobial and wound healing properties of honey.
“Honey has a number of properties that make it effective against bacterial growth, including its high sugar content, low moisture content, gluconic acid – which creates an acidic environment – and hydrogen peroxide. It has also been shown to reduce inflammation and swelling.”
Researchers have also reported that applying honey can be used to reduce amputation rates among diabetes patients.
Stressing that patients should always check with their surgeon before applying any substance to post-operative wounds, Dr Khan adds that studies have found that honey offers a number of benefits.
“It can be used to sterilise infected wounds, speed up healing and impede tumours, particularly in keyhole surgery.”
Studies have suggested that honey should be applied at regular intervals, from hourly to twice daily and that wounds can become sterile in three to 10 days.
“The research suggests that honey seems to be especially indicated when wounds become infected or fail to close or heal” says Dr Khan. “It is probably even more useful for healing the wounds left by laparoscopic surgery to remove cancers.”
18 studies covering more than 60 years were included in the review. The authors also looked at other substances used for wound healing, including maggots, which were also commonly used before the introduction of antibiotics and are enjoying a revival.
The team also discovered an ancient manuscript that used wine dregs, juniper prunes and beer, but point out that that has not been tried and tested in recent years!
“Our research suggests that surgeons should seriously consider using honey for post-operative wounds and offer this to patients” concludes Dr Khan. “We would also encourage patients to ask about honey as an option, but stress that they should always follow their surgeon’s advice and not try any home remedies.”
###
Honey: nutritional and medicinal value. Khan et al. IJCP, the International Journal of Clinical Practice. 61.10, pp 1705-1707. (October 2007)
Resource:Eurekalert October 2007

Thursday, 20 September 2007

Postcranial evidence from early Homo from Dmanisi, Georgia


Lordkipanidze et al (2007)

The Plio-Pleistocene site of Dmanisi, Georgia, has yielded a rich fossil and archaeological record documenting an early presence of the genus Homo outside Africa. Although the craniomandibular morphology of early Homo is well known as a result of finds from Dmanisi and African localities, data about its postcranial morphology are still relatively scarce. Here we describe newly excavated postcranial material from Dmanisi comprising a partial skeleton of an adolescent individual, associated with skull D2700/D2735, and the remains from three adult individuals. This material shows that the postcranial anatomy of the Dmanisi hominins has a surprising mosaic of primitive and derived features. The primitive features include a small body size, a low encephalization quotient and absence of humeral torsion; the derived features include modern-human-like body proportions and lower limb morphology indicative of the capability for long-distance travel. Thus, the earliest known hominins to have lived outside of Africa in the temperate zones of Eurasia did not yet display the full set of derived skeletal features.

Source:Nature 449, 305-310 (20 September 2007)
Treasure trove of Homo erectus foundDozens of fossils reveal four primative humans.
article by Rex Dalton

A trove of the oldest human skeletal bones outside Africa is reported in Nature this week — a find that will help researchers to improve their understanding of the biology of the 1.8-million-year-old hominins. The work, led by researchers from the Georgian National Museum in Tbilisi, describes three-dozen fossils from the skeletons of four primitive Homo erectus individuals found in recent years at Dmanisi in Georgia, central Asia. H. erectus is thought to have migrated across Asia after coming out of Africa, where the oldest relative of man is traced to nearly 7 million years ago. H. erectus fossils have been found from Africa across Asia as far as Indonesia. Typically there are only a few scattered fossils at one location. A single site with so many bones from so many individuals is rare. And they date back to very soon after H. erectus's exodus from Africa."Dmanisi is a real gift, because nothing in the world exists like this for this time," says lead author David Lordkipanidze."The really important point is you have multiple individuals from the same time and location," adds Tim White, a palaeoanthropologist at the University of California, Berkeley, who was not involved in the work. Together the specimens — three adults and an adolescent — present a much better picture of what the species was like as a whole than would a single skeleton. With one individual, experts note, it is difficult to determine whether a feature such as leg length is typical of the entire species or just characteristic of that one individual. With four skeletons, you start to have a data set that you can reasonably compare with modern humans, says Alan Walker, a palaeoanthropologist at Pennsylvania State University in University Park.Researchers are now attempting to link these fossils to three skulls, a cranium and a mandible all found previously in the same dig site.Size smallThe Dmanisi site — which continues to yield fossils annually — was near a lava flow where the primitive humans are thought to have scavenged carcasses for meat. But H. erectus then became a victim of carnivores, with their collective bones marked by animal teeth and found in a lair-like deposit.Lordkipanidze and his colleagues note that the skeletal fossils of shoulder, arm, spine and leg show that the individuals were small (about 50 kilograms on a frame of some 150 centimetres tall), had modern-human body-limb proportions, and legs capable of long-distance travel.This reflects variation expected in the species, notes anatomist Owen Lovejoy of Kent State University in Ohio. It is known that H. erectus living in colder climates had shorter limbs compared with those from the hotter environs of Africa.Even though this sample provides a good look at H. erectus in this time and place, experts caution against drawing broad conclusions about H. erectus. As more fossils are reported in the near future, as is expected, the growing Dmanisi collection will allow researchers to describe our relatives more definitively.
Source:Nature doi:10.1038/news070917-6

Monday, 17 September 2007

These Legs were Made for Fighting;Human Ancestors had Short Legs for Combat, not Just Climbing


Ape-like human ancestors known as australopiths maintained short legs for 2 million years because a squat physique and stance helped the males fight over access to females, a University of Utah study concludes.
"The old argument was that they retained short legs to help them climb trees that still were an important part of their habitat," says David Carrier, a professor of biology. "My argument is that they retained short legs because short legs helped them fight."
The study analyzed leg lengths and indicators of aggression in nine primate species, including human aborigines. It is in the March issue of the journal Evolution.
Creatures in the genus Australopithecus – immediate predecessors of the human genus Homo – had heights of about 3 feet 9 inches for females and 4 feet 6 inches for males. They lived from 4 million to 2 million years ago.
"For that entire period, they had relatively short legs – longer than chimps' legs but shorter than the legs of humans that came later," Carrier says.
"So the question is, why did australopiths retain short legs for 2 million years? Among experts on primates, the climbing hypothesis is the explanation. Mechanically, it makes sense. If you are walking on a branch high above the ground, stability is important because if you fall and you're big, you are going to die. Short legs would lower your center of mass and make you more stable."
Yet Carrier says his research suggests short legs helped australopiths fight because "with short legs, your center of mass is closer to the ground. It's going to make you more stable so that you can't be knocked off your feet as easily. And with short legs, you have greater leverage as you grapple with your opponent."
While Carrier says his aggression hypothesis does not rule out the possibility that short legs aided climbing, but "evidence is poor because the apes that have the shortest legs for their body size spend the least time in trees – male gorillas and orangutans."
He also notes that short legs must have made it harder for australopiths "to bridge gaps between possible sites of support when climbing and traveling through the canopy."
Nevertheless, he writes, "The two hypotheses for the evolution of relatively short legs in larger primates, specialization for climbing and specialization for aggression, are not mutually exclusive. Indeed, selection for climbing performance may result in the evolution of a body configuration that improves fighting performance and vice versa."
Great Apes' Short Legs Provide Evidence for Australopith Aggression
All modern great apes – humans, chimps, orangutans, gorillas and bonobos – engage in at least some aggression as males compete for females, Carrier says.
Carrier set out to find how aggression related to leg length. He compared Australian aborigines with eight primate species: gorillas, chimpanzees, bonobos, orangutans, black gibbons, siamang gibbons, olive baboons and dwarf guenon monkeys. Carrier used data on aborigines because they are a relatively natural population.
For the aborigines and each primate species, Carrier used the scientific literature to obtain typical hindlimb lengths and data on two physical features that previously have been shown to correlate with male-male competition and aggressiveness in primates:
The weight difference between males and females in a species. Earlier studies found males fight more in species with larger male-female body size ratios.
The male-female difference in the length of canine teeth, which are next to the incisors and are used for biting during fights.
Carrier used male-female body size ratios and canine tooth size ratios as numerical indicators for aggressiveness because field studies of primates have used varying criteria to rate aggression. He says it would be like having a different set of judges for each competitor in subjective Olympic events like diving or ice dancing.
The study found that hindlimb length correlated inversely with both indicators of aggressiveness: Primate species with greater male-female differences in body weight and length of the canine teeth had shorter legs, and thus display more male-male combat.
There was no correlation between arm length and the indicators of aggression. Carrier says arms are used for fighting, but "for other things as well: climbing, handling food, grooming. Thus, arm length is not related to aggression in any simple way."
Verifying the Findings
Carrier conducted various statistical analyses to verify his findings. First, he corrected for each species' limb lengths relative to their body size. Primates with larger body sizes tend to have shorter legs, humans excepted. Without taking that into account, the correlation between body size and aggression indicators might be false.
Another analysis corrected for the fact different primate species are related. For example, if three closely related species all have short legs, it might be due to the relationship – an ancestor with short legs – and not aggression.
Even with the corrections, short legs still correlated significantly with the two indicators of aggressiveness.
The study also found that females in each primate species except humans have relatively longer legs than males. "If it is mainly the males that need to be adapted for fighting, then you'd expect them to have shorter legs for their body size," Carrier says.
He notes there are exceptions to that rule. Bonobos have shorter legs than chimps, yet they are less aggressive. Carrier says the correlation between short legs and aggression may be imperfect because legs are used for many other purposes than fighting.
Humans "are a special case" and are not less aggressive because they have longer legs, Carrier says. There is a physical tradeoff between aggression and economical walking and running. Short, squat australopiths were strong and able to stand their ground when shoved, but their short legs made them ill-suited for distance running. Slender, long-legged humans excel at running. Yet, they also excel at fighting. In a 2004 study, Carrier made a case that australopiths evolved into lithe, long-legged early humans only when they learned to make weapons and fight with them.
Now he argues that even though australopiths walked upright on the ground, the reason they retained short legs for 2 million years was not so much that they spent time in trees, but "the same thing that selected for short legs in the other great apes: male-male aggression and competition over access to reproductively active females."
In other words, shorter legs increased the odds of victory when males fought over access to females – access that meant passing their genetic traits to offspring.
Yet, "we don't really know how aggressive australopiths were," Carrier says. "If they were more aggressive than modern humans, they were exceptionally nasty animals."
Why Should We Care that Australopiths Were Short and Nasty?
"Given the aggressive behavior of modern humans and apes, we should not be surprised to find fossil evidence of aggressive behavior in the ancestors of modern humans," Carrier says. "This is important because we have a real problem with violence in modern society. Part of the problem is that we don’t recognize we are relatively violent animals. Many people argue we are not violent. But we are violent. If we want to prevent future violence we have to understand why we are violent."
"To some extent, our evolutionary past may help us to understand the circumstances in which humans behave violently," he adds. "There are a number of independent lines of evidence suggesting that much of human violence is related to male-male competition, and this study is consistent with that."
Nevertheless, male-male competition doesn’t fully explain human violence, Carrier says, noting other factors such as hunting, competing with other species, defending territory and other resources, and feeding and protecting offspring.


Source: University of Utah,2007

Study identifies energy efficiency as reason for evolution of upright walking

A new study provides support for the hypothesis that walking on two legs, or bipedalism, evolved because it used less energy than quadrupedal knucklewalking.
David Raichlen, an assistant professor of anthropology at The University of Arizona, conducted the study with Michael Sockol from the University of California, Davis, who was the lead author of the paper, and Herman Pontzer from Washington University in St. Louis.
Raichlen and his colleagues will publish the article, "Chimpanzee locomotor energetics and the origin of human bipedalism" in the online early edition of the Proceedings of the National Academy of Sciences (PNAS) during the week of July 16. The print issue will be published on July 24.
Bipedalism marks a critical divergence between humans and other apes and is considered a defining characteristic of human ancestors. It has been hypothesized that the reduced energy cost of walking upright would have provided evolutionary advantages by decreasing the cost of foraging.
"For decades now researchers have debated the role of energetics and the evolution of bipedalism," said Raichlen. "The big problem in the study of bipedalism was that there was little data out there."
The researches collected metabolic, kinematic and kenetic data from five chimpanzees and four adult humans walking on a treadmill. The chimpanzees were trained to walk quadrupedally and bipedally on the treadmill.
Humans walking on two legs only used one-quarter of the energy that chimpanzees who knuckle-walked on four legs did. On average, the chimpanzees used the same amount of energy using two legs as they did when they used four legs. However, there was variability among chimpanzees in how much energy they used, and this difference corresponded to their different gaits and anatomy.
"We were able to tie the energetic cost in chimps to their anatomy," said Raichlen. "We were able to show exactly why certain individuals were able to walk bipedally more cheaply than others, and we did that with biomechanical modeling."
The biomechanical modeling revealed that more energy is used with shorter steps or more active muscle mass. Indeed, the chimpanzee with the longest stride was the most efficient walking upright.
"What those results allowed us to do was to look at the fossil record and see whether fossil hominins show adaptations that would have reduced bipedal energy expenditures," said Raichlen. "We and many others have found these adaptations [such as slight increases in hindlimb extension or length] in early hominins, which tells us that energetics played a pretty large role in the evolution of bipedalism."


Source: University of Arizona Communications; 2007

Was ability to run early man's Achilles heel?


The earliest humans almost certainly walked upright on two legs but may have struggled to run at even half the speed of modern man, new research suggests.
The University of Manchester study- presented to the BA (British Association for the Advancement of Science) Festival of Science in Yorktoday (Tuesday)- proposes that if early humans lacked an Achilles tendon, as modern chimps and gorillas do, then their ability to run would have been severely compromised.
"Our research supports the belief that the earliest humans used efficient bipedal walking rather than chimp-like 'Groucho' walking," said Dr Bill Sellers, who led the research in the University's Faculty of Life Sciences.
"But if, as seems likely, early humans lacked an Achilles tendon then whilst their ability to walk would be largely unaffected our work suggests running effectiveness would be greatly reduced with top speeds halved and energy costs more than doubled.
"Efficient running would have been essential to allow our ancestors to move from a largely herbivorous diet to the much more familiar hunting activities associated with later humans. What we need to discover now is when in our evolution did we develop an Achilles tendon as knowing this will help unravel the mystery of our origins."
Dr Sellers, who recently published research on the running speeds of five meat-eating dinosaurs, used the same computer software to generate a humanoid bipedal computer model using data from a hominid fossil skeleton called 'Lucy' and hominid footprints preserved in ash at Laetoli in Tanzania.
"The skeletons and footprints from some of the earliest members of the human lineage- the early hominids- provide the best clues we have to how we progressed down the pathway to modern human walking and running," said Dr Sellers.
"We have borrowed techniques from other scientific disciplines - robotics, computer science and biomechanics - in an attempt to 'reverse engineer' fossil skeletons; we use what we know about skeletons and the muscles to build a computer model of the fossil species we are interested in.
"This model is a virtual robot where we can activate muscles and get it to move its legs in a physically realistic fashion; the tricky bit is getting it to actually walk or run without falling over.
"However, if we use big enough computers and let the model fall over enough times it is possible for the simulation to learn which muscles to fire and when in order to get the model to walk properly. Even better we can ask the computer to find ways of minimising fuel cost and maximising top speed since that is what we think animals have to do."
Dr Sellers initially looked at walking and his models suggested that even as early as 3.5 million years ago our human ancestors were able to walk as efficiently as modern humans. His research also showed that they preferred to walk a little slower than we do but only because they were much smaller and had quite short legs.
The team also used the computer model to look at particular parts of the human locomotion system, including the Achilles tendon, which they showed acts like a big spring to store energy during running; when the tendon was removed from the model the top running speed was greatly reduced.
"We have only just started to look at running and so there are still plenty of questions to answer," said Dr Sellers. "But whilst these very early fossils could walk well, our initial findings suggest that efficient running came about quite a bit later in the fossil record.
"How we evolved from our common ancestor with chimpanzees six million years ago is a fundamental question. Walking upright seems to be the very first thing that distinguishes our ancestors from other apes, so finding out about this should help us map the evolutionary pathway to modern humans.
"The next really interesting question is to look in more detail at running. It has been suggested that our ability to run for long distances took a lot longer to evolve than our ability to walk and that this is a defining feature of our very close relatives in our genus. Our techniques should let us get to the bottom of this question because it will let us measure the running abilities of our fossil ancestors directly."

Source:Manchester University; Faculty of Life Science. 17 th September 2007

Tuesday, 11 September 2007

Our upright walking started in the trees

Our ancient tree-dwelling ancestors stood upright on two legs – a trait modern humans have retained, while other great apes have evolved four-legged knuckle-walking, researchers say.
It was one of the characteristics that was supposed to define the ancestral human line from our great ape cousins: We walk upright, while chimps and gorillas walk on four legs, using their knuckles.
Now it seems that we did not evolve from knuckle-walkers – bipedalism apparently arose far earlier in evolutionary history, when our ancestors were still in the trees.
Several scenarios have been proposed to explain why we came to walk on two legs, from the idea that it allowed our ancestors to
feed more efficiently and carry infants, to the idea that the posture reduced our exposure to sunlight and so gave us longer to forage.
Canopy skills
Susannah Thorpe, of the University of Birmingham, UK, and colleagues have made extensive observations of the most arboreal of the modern great apes, the orang-utan, and come to another conclusion, that bipedalism evolved to help us move about the forest canopy.
"The orang-utan is the only great ape still living in its ancestral habitat," says Thorpe, making them good models for understanding the selection pressures on ancestral apes.
Thorpe spent a year recording orang-utan behaviour in the Gunung Leuser National Park in Sumatra, Indonesia, and from nearly 3000 observations of locomotion, the team concluded that the apes were more likely to walk on two legs - using their hands to guide them - when they are on the thinnest branches, less than 4 centimetres in diameter.
On medium-sized branches - those greater than 4 cm but less than 20 cm diameter - the apes tended to walk bipedally, but used their arms to support their weight by swinging or hanging.
Only on the largest branches, with a diameter greater than 20 cm, did the animals walk on all fours.
Fruits of bipedalism
Since orang-utans are fruit eaters, and fruit is more likely to be found on the ends of thinner branches, the ability to walk out along them is advantageous. Since they also spend most of their time in the trees, the ability to move over thinner branches helps when it comes to crossing from tree to tree and traversing the canopy, says Thorpe.
When walking bipedally, orang-utans extended their legs at the knee and hip to give them a straighter posture, in contrast to what happens when chimps try to walk on two legs. Chimps are forced to waddle with bent knees and their torso bent over at the hip. When humans run on springy surfaces they also keep their legs straight, like orang-utans, Thorpe points out.
"Walking upright and balancing themselves by holding branches with their hands is an effective way of moving on smaller branches," says Robin Crompton of the University of Liverpool, UK, who was also involved in the study.
"It helps to explain how early human ancestors learnt to walk upright while living in the trees, and how they would have used this way of moving when they left the trees for a life on the ground."
Ground foragers
So, rather than evolving to walk on two feet after scrabbling around on the floor on all fours, the theory suggests our ancestors already had the rudimentary means of walking on two feet before they even left the trees.
When the ancestors of chimps and gorillas left the trees, however, they needed to maintain the ability to climb tree trunks. This need for tree-climbing strength and anatomy guided their evolution at the expense of more efficient terrestrial movement, and therefore led to knuckle-walking, says Crompton.
Orang-utans are the most distant of our relatives among the great apes, followed by gorillas, and then bonobos and chimpanzees. The ancestors of the latter two species split from the human line around 6 million years ago; the orang-utan ancestor split from the human ancestor around 10 million years ago.
Thorpe and colleagues suggest that at sometime in the Miocene epoch - 24 to 5 million years ago - the increased gaps in the forest canopy that came about as a result of climate fluctuations had a profound effect on our ape ancestors.
Some of them - the ancestors of chimps and gorillas - specialised on climbing high into the canopy and crossing the gaps between trees by knuckle walking. Others - the ancestors of humans - retained their ability to walk on two legs, and specialised on collecting food from smaller trees and the ground.
Plausible mechanism
The idea of an arboreal origin for human bipedalism has been proposed before, says Chris Stringer, a palaeontologist at the Natural History Museum, London. "Nevertheless, this is the best observational data on the importance of hand-assisted bipedalism to orangs, and its possible implications for the evolution of human bipedalism."
Since all the sites which have yielded fossil evidence of our earliest ancestors were forested or wooded, rather than open, Stringer says, "arboreal bipedalism is certainly a very plausible mechanism for the origins of walking upright."
Paul O’Higgins, of the Functional Morphology and Evolution unit at the University of York, UK, says the finding makes it more difficult to find a feature unique to the human ancestral line. "If extended hip and knee bipedalism did indeed arise in the distant past, this makes the task of identifying possible ancestors of the human line much more difficult," he says.
There has been tantalising fossil evidence suggesting an early origin for bipedalism, says Crompton. "And the orang-utan is the only ape with a knee joint similar to that of humans."
Despite this, the idea that all apes at one stage had the potential to walk on two legs and that from this starting point some evolved to knuckle walk and some evolved bipedalism has been resisted. "Perhaps we’ve been too focused on the African apes," says Thorpe. "The trend has been to look at them to explain human evolution."


31 May 2007
NewScientist.com news service
Rowan Hooper
Journal reference: Science (DOI: 10.1126/science.1140799)

Ancient gene kit came in handy for limbs


The master genes controlling development in the primitive animal known as the paddlefish turn out to be unexpectedly similar to those controlling the development of limbs in land animals. Rather than evolving a new set of control genes for their limbs, it seems that our amphibian ancestors adapted the genes their own ancestors used to develop fins.
The paddlefish Polyodon spathula is often referred to as a "living fossil", an organism that is similar to no known species apart from fossils. Most previous genetic work on fish has been done on the more highly evolved zebrafish. This appeared to show that the Hox family of control genes in land animals and fish were different, implying land animals had evolved new genes to control growth of hands and feet.
Hox genes control the alignment and polarisation of body structures in all animals, separating head from tail. In fish they arrange the structures of fins, and in land animals the structure of limbs. Zebrafish develop their fins in a single stage, in which Hox genes produce parallel stripes that underlie fin structures. Mice and chickens have a second phase of development in which Hox genes turn on only in the regions that become a hand or foot.
"The logical explanation was that since fish don't have hands, they don't have a second stage of Hox gene development, so [addition of] the second stage should correlate with evolution of the hand," says Marcus Davis of the University of Chicago. But zebrafish are highly evolved, so he wondered if they had lost the ancestral form of fin development.
Davis and colleagues looked at Hox genes in the paddlefish, a primitive relative of the sturgeon, because it is relatively unevolved. They found that the little arm fins of paddlefish develop in two phases, implying that the second phase of Hox gene expression had evolved long before arms and legs, but was lost in zebrafish (Nature, vol 447, p 473).
That ancient set of genes played a key role in helping vertebrates crawl onto land. Tiktaalik, the fish with feet discovered last year (New Scientist, 8 April 2006, p 14), "already had the toolkit needed to modify the part of the limbs furthest out", Davis says. As ancestral amphibians moved onto land, they used their existing genetic tools to adapt their limbs.
“As amphibians moved onto land they used their existing genetic tools to adapt their limbs to the new environment”
"Here's something we thought was invented from scratch, but it was there in a deep ancestor of tetrapods," says Sean Carroll, a developmental biologist at the University of Wisconsin, Madison.


From issue 2605 of New Scientist magazine, 23 May 2007, page 18

Saturday, 1 September 2007

The evolution of human running: Effects of changes in lower-limb length on locomotor economy

Previous studies have differed in expectations about whether long limbs should increase or decrease the energetic cost of locomotion. It has recently been shown that relatively longer lower limbs (relative to body mass) reduce the energetic cost of human walking. Here we report on whether a relationship exists between limb length and cost of human running. Subjects whose measured lower-limb lengths were relatively long or short for their mass (as judged by deviations from predicted values based on a regression of lower-limb length on body mass) were selected. Eighteen human subjects rested in a seated position and ran on a treadmill at 2.68 m s−1 while their expired gases were collected and analyzed; stride length was determined from videotapes. We found significant negative relationships between relative lower-limb length and two measures of cost. The partial correlation between net cost of transport and lower-limb length controlling for body mass was r = −0.69 (p = 0.002). The partial correlation between the gross cost of locomotion at 2.68 m s−1 and lower-limb length controlling for body mass was r = −0.61 (p = 0.009). Thus, subjects with relatively longer lower limbs tend to have lower locomotor costs than those with relatively shorter lower limbs, similar to the results found for human walking. Contrary to general expectation, a linear relationship between stride length and lower-limb length was not found.


Steudel-Numbers, K. L. Weaver, T. D. Wall-Scheffler,C. M. (2007)Department of Zoology, University of Wisconsin, Madison, WI 53706, USA

Monday, 27 August 2007

The foot and other evidence from the lower limb provide clear evidence for bipedal locomotion


A 3.3-million-year-old fossilised remains of a human-like child have been unearthed in Ethiopia's Dikika region, providing an opportunity to study the skeletal remainns of a child.The body was believed to be covered soon after death by floodwater and has remained preserved in a block of sandstone, taking a team lead by Zeresenay Alemseged, five years to excavate.


The cranial evidence indicates a slow, indicating a gradual development with an extended childhood, which is regarded as a very human trait - probably to enable our higher functions to develop.
The foot and other evidence from the lower limb provide clear evidence for bipedal locomotion.






Source: http://news.bbc.co.uk/1/hi/sci/tech/5363328.stm

Tuesday, 21 August 2007

Origin of Bipedalism, seems most closely tied to environmental changes

During the past 100 years, scientists have tossed around a great many hypotheses about the evolutionary route to bipedalism, to what inspired our prehuman ancestors to stand up straight and amble off on two feet.
Now, after an extensive study of evolutionary, anatomical and fossil evidence, a team of paleoanthropologists has narrowed down the number of tenable hypotheses to explain bipedalism and our prehuman ancestors’ method of navigating their world before they began walking upright.
The hypothesis they found the most support for regarding the origin of bipedalism is the one that says our ancestors began walking upright largely in response to environmental changes – in particular, to the growing incidence of open spaces and the way that changed the distribution of food.
In response to periods of cooling and drying, which thinned out dense forests and produced “mosaics” of forests, woodlands and grasslands, it seems likely that “some apes maintained a
forest-oriented adaptation, while others may have begun to exploit forest margins and grassy woodlands,” said paleoanthropologist Brian Richmond, lead author in the new study. The process of increasing commitment to bipediality probably involved “an extended and complex opening of habitats, rather than a single, abrupt transition from dense forest to open savanna,” he said.
Richmond, from the University of Illinois, with anthropologist David Begun from the University of Toronto and David Strait from the department of anatomy at the New York College of Osteopathic Medicine, describe their findings, which involved a comprehensive review and analyses of the five leading hypotheses on the origin of bipedalism, in a recent issue of the Yearbook of Physical Anthropology. Other hypotheses that remain viable, according to the team: “freeing” the hands for carrying or for some kind of tool use, and an increased emphasis on foraging from branches of small fruit trees, which is the context in which modern chimpanzees spend the most time on two legs.
For their study, the researchers combined data from biomechanics – movement and posture, pressure distributions and strain gauge – and from finger-shape growth and development. They found that our prehuman ancestors had terrestrial features in the hands and feet, climbing features throughout the skeleton, and knuckle-walking features in the wrist and hand; that finger curvature is responsive to changes in arboreal activity during growth. Evidence from the wrist joint, in particular, “suggests that the earliest humans evolved bipedalism from an ancestor adapted for knuckle-walking on the ground and climbing in trees.”
The YPA article, according to Richmond, is “the first attempt in decades to bring together all of the available evidence for the argument that the earliest human biped evolved from ancestors that both knuckle-walked and climbed trees, rather than from ancestors living exclusively in trees and ‘coming down from the trees,’ or walking on the ground in ways similar to modern baboons.”
http://www.eurekalert.org/pub_releases/2002-04/uoia-oob043002.php>

The evolution of human running: Effects of changes in lower-limb length on locomotor economy

Previous studies have differed in expectations about whether long limbs should increase or decrease the energetic cost of locomotion. It has recently been shown that relatively longer lower limbs (relative to body mass) reduce the energetic cost of human walking. Here we report on whether a relationship exists between limb length and cost of human running. Subjects whose measured lower-limb lengths were relatively long or short for their mass (as judged by deviations from predicted values based on a regression of lower-limb length on body mass) were selected. Eighteen human subjects rested in a seated position and ran on a treadmill at 2.68 m s−1 while their expired gases were collected and analyzed; stride length was determined from videotapes. We found significant negative relationships between relative lower-limb length and two measures of cost. The partial correlation between net cost of transport and lower-limb length controlling for body mass was r = −0.69 (p = 0.002). The partial correlation between the gross cost of locomotion at 2.68 m s−1 and lower-limb length controlling for body mass was r = −0.61 (p = 0.009). Thus, subjects with relatively longer lower limbs tend to have lower locomotor costs than those with relatively shorter lower limbs, similar to the results found for human walking. Contrary to general expectation, a linear relationship between stride length and lower-limb length was not found.

Karen L. Steudel-Numbers , Timothy D. Weaver\and Cara M. Wall-Schefflera
Department of Zoology, University of Wisconsin, Madison, WI 53706, USA
Received 19 September 2006; accepted 9 April 2007. Available online 14 June 2007. Corresponding author. Tel.: +1 608 263 5079; fax: +1 608 265 6320.1 Current address: Department of Anthropology, University of California, One Shields Avenue, Davis, CA 95616, USA.

Sunday, 12 August 2007

Opinions from podiatrists practising accupuncture?


Oetzi The Tyrolean Iceman - European Acupuncture 2000 Years before China?

The Tyrolean Iceman (1), by far the oldest European mummified human body (5200 years old), shows 15 well-preserved tattoo groups on his back and legs, none of which appears to have ornamental importance. The tattoos have a simple linear geometric shape and are located on parts of the body that are not expected to be displayed (2). Moreover, several tattoos that would have entailed superficial skin puncture seem to be located on Chinese acupuncture points.
puncture seem to be located on Chinese acupuncture points.
The tattoos were therefore investigated morphometrically, and photographs were subsequently overlayed by topographic representations of acupuncture points (3). According to the expert opinion of three accredited acupuncturists (4), nine of the 15 tattoos could be identified as being located on or within 5 millimeters of acupuncture points. Five tattoo groups on the back of the Iceman were located in close proximity, or directly over, acupuncture points of the urinary bladder (UB) channel. A close match between the acupuncture point UB 60 and one of the two tattoo crosses near the left, lateral ankle was observed.
The theory of acupuncture predicts that perforation or irritation of the skin at specific locations, the acupuncture points, results in modified function of related, not necessarily adjacent, organs, allowing relief of pain or inflammation.
It is known from computer tomography (5) that the iceman suffered from arthrosis of the lumbar spine. Acupuncture points used for treatment of this condition (3) coincide with tattoos found along the UB channel.
These findings raise the possibility that the practice of therapeutically intended acupuncture originated long before the medical tradition of ancient China (approximately 1000 B.C.) and that its geographical origins were Eurasian rather than East-Asian, consistent with far-reaching intercultural contacts of prehistoric mankind.




H. Seidler et al., Science, 258, 455 (1992); K. Spindler, The Man in the Ice (Weidenfeld & Nicolson, London, 1994).
T. Sjøvold et al., in Der Mann im Eis, K. Spindler et al., Eds. (Springer, Vienna-New York, 1995), vol. 2, pp. 279-286.
3. Beijing, Shanghai, and Nanjing colleges of traditional Chinese medicine, Essentials of Chinese Acupuncture (Foreign Languages Press, Beijing, 1980).
F. Bahr, L. Dorfer, and S. Suwanda, presi
presidents of the German, Austrian, and Swiss academies of acupuncture, respectively.

D. zur Nedden and K. Wicke, in Der Mann im Eis, F. Höpfel, W. Platzer, K. Spindler, Eds. (Univ. of Innsbruck, Innsbruck, Austria, 1992), vol. 1, pp. 131-148.



Source: The Journal of Chinese Medicine


<http://theamt.com/modules.php?name=News&file=article&sid=218>

Tuesday, 7 August 2007

Interesting questions on foot evolution?

Palaeopodiatry :would like to thank Robert for sharing his work with us.

Dr.Robert Kidd. BA (Hons) PhD, Associate Professor,Human Anatomy School of Biomedical and Health ScienceUniversity of Western Sydney

Little Foot and big thoughts—a re-evaluation of the Stw573 foot from
Sterkfontein, South Africa
.
R. Kidd, C. Oxnard ,HOMO—Journal of Comparative Human Biology 55 (2005) 189–212

The part of the fossil assemblage Stw573 consisting of some medial foot bones was initially reported by Clarke & Tobias (Science 269 (2002) 521). They found it to have both ape- and human-like qualities, being human-like proximally and ape-like distally. We have undertaken a re-examination of this pedal assemblage using a multivariate analysis; We report an essentiallyape-like morphology proximally and a human-like morphology distally; the talus and navicular were found to be ape-like and the medial cuneiform human-like.

Introduction

That the human foot evolved from some variety of primitive hominoid ancestral stock is not held in doubt. In doing so it has changed in many features, some large scale and obvious, others more subtle. Three large scale modifications stand apart. These may be summarised as follows: (1) a change in the size and proportions of the pedal skeletal segments with the tarsus becoming much greater in humans; (2) the presence of a divergent first ray and opposable first digit in all apes but not in humans; and (3) the presence of the related longitudinal and transverse arch structures in humans but their absence in all other hominoids. These major features, plus a myriad of minor ones distinguish the human foot from that of apes. There is little doubt that the human foot evolved in a mosaic manner, with certain critical features attaining a human form before others. To understand their sequence, a number of questions need to be answered. For instance, did the lateral pedal column, broadly describing the lateral longitudinal arch, become human-like before or after the medial longitudinal arch? Similarly, did the first toe achieve a state of apposition before or after arch formation? And at what stage did the segmental
proportions of the evolving foot become human-like? Some clue may be found by scrutiny of the fossil record, though this is frustratingly sparse with no complete prehuman specimens being available. The most complete is that from East Africa, the OH8 foot from Olduvai, but even this is missing certain vital parts, namely portions of the calcaneus, the metatarsal heads and all digits.

In a previous study (Kidd et al 1994, 1996) the four hindmost tarsal elements of this foot were studied morphometrically and unequivocal evidence for mixed functional affinities was found, the medial side being ape-like and the lateral column (with due caveat for the incomplete calcaneus) being human-like. The medial cuneiform was not reported. Clarke and Tobias (1995) also report on a fossil foot assemblage, that known as Stw573, consisting of the talus, navicular, medial cuneiform and first ray fragment from Sterkfontein Cave, Member 2 and attributed to the species Australopithecus africanus. They also observed mixed affinities, both human- and ape-like features, though in a manner differing from our findings with OH8; they describe the talus to be essentially human-like, the navicular to be of mixed ape and human morphology, and the medial cuneiform to be largely ape-like. Their findings are clearly in conflict with those of the OH8 study, and they do not seem to be reconcilable with either the OH8 findings of Kidd et al (1996), nor the model of human pedal evolution predicted in part from the OH8 study (Kidd 1995, 1998, 1999). The basis of the findings of Clarke and Tobias is not quantitative; they do not report a metrical analysis. It is appropriate, therefore, to undertake a morphometric analysis of the Stw573 fossil assemblage to establish the functional affinities of the tarsal elements and to see if the quite different findings of the two assemblages may be reconciled. In addition, in order to present a complete and unambiguous picture, the OH8 foot is revisited with an analysis of the medial cuneiform to complete the analyses presented in Kidd et al (1996).

Shoe Historian

A collection of short anecdotes and funny stories about feet and shoes. The sum total will mean, read this and you will never trust yourself alone with a pair of shoes again. Cameron Kippen is a shoe historian and podiatrist, interested in informing and entertaining readers fascinated by feet and shoes.

foot talk (link)

Monday, 6 August 2007

One million old footprints


Pakistani archaeologists have found two, over one million years old human footprints preserved on sandstone in the Margalla Hills, which surround the capital.World-renowned archaeologist and historian Dr Ahmad Hassan Dani of the Taxila Institute of Asian Civilisations, Quaid-i-Azam University, made the discovery.
A footprint of one foot is in complete and well-preserved form, while another is broken from the finger side, which is also of the same size in comparative manner, the Dawn reports. The notable marks of the feet are the clear veins and opposite folded appearance, the report adds.
According to Dr. Azad, further research of the footmarks using anthropological and geophysical methods, might give more clues.The recent discovery is the continuity of the Indusian Research Cell's earlier research about human evolution, which previously revealed a fossilised upper jaw from the site of Dhudhumber, foot, and handprints from Attock and Palaeolithic cave from the Margalla Hills.

Pakistan is said to have abundant fossilised evidences of Pre-Cambrian to Holocene epochs, the earliest evidences of the anthropoid existence, the earliest cultural centre at Mehargarh (contemporary of Jericho and Jarmo) and most advanced civilisation of the world (Indus Valley). According to Dr. Azad the formation of the Margalla Hills goes back to the Miocene epoch. The dominant limestone of the Margalla is also mixed with the sand stone.

Pasted from, Islamabad, July 28,2007:
<http://story.malaysiasun.com/index.php/ct/9/cid/303b19022816233b/id/268787/cs/1/>

Tianyuan-toebone "...pushes back earliest known evidence for footware by 10,000 years....Professor Eric Trinkaus."

China's earliest modern human

The remains of one of the earliest modern humans to inhabit eastern Asia have been unearthed in a cave in China. Researchers found 34 bone fragments belonging to a single individual at the Tianyuan Cave, near Beijing. Radiocarbon dates, obtained directly from the bones, show the person lived between 42,000 and 39,000 years ago.
"For this time period, which is critical for understanding the spread of modern humans around the world, we have two well-dated human fossils from eastern Asia," said co-author Professor Erik Trinkaus, from Washington University in St Louis, US. "We have remains from the Niah Cave from Sarawak on Borneo, and now this specimen from China. As you go west, the next specimens are from Lebanon. There's nothing in between."
The Tianyuan remains display diagnostic features of modern H. sapiens. But co-author Erik Trinkaus and his colleagues argue, controversially, that the bones also display features characteristic of earlier human species, such as relatively large front teeth. The most likely explanation, they argue, is interbreeding between early modern humans emerging from Africa and the archaic populations they encountered in Europe and Asia.
The view of interbreeding between Homo sapiens and archaic humans is controversial. Other palaeoanthropologists say that some of these features are simply retained from ancient African ancestors. And most genetic evidence gathered from present-day humans does not appear to support significant interbreeding between modern humans from Africa and archaics.
The researchers' analysis of the bones has revealed several interesting details about the Tianyuan individual's lifestyle. The person's age at death was estimated by how much the teeth had worn down. This put the individual in their late 40s or 50s. But the lack of a pelvis among the remains means that it is not possible to say with any certainty what sex the human was. The Tianyuan specimen shows several signs of disease. The individual had lost a number of teeth before death, not unusual considering their age. The researchers also identified several lesions, or growths, on the leg bones, which appear to have been caused by a condition affecting the muscle attachments around both knees. Whatever condition these were caused by, however, it does not appear to have disabled the person, because the remainder of the leg bones suggest they kept active. The single toe bone [the second proximal phalanx] which was unearthed seems to suggest the individual wore shoes, pushing back the earliest known evidence for footwear by about 10,000 years.
An earlier study by Professor Trinkaus shows that human small toes became weaker during the stage of prehistory known as the Upper Palaeolithic, and that this can probably be attributed to the adoption of sturdy shoes. The invention of rugged shoes reduced humans' reliance on strong, flexile toes to grip and balance.
Sources: EurekAlert! (2 April 2007)



The origin of human bipedalism
While no one has an authoritative answer, anthropologists have long theorized that early humans began walking on two legs as a way to reduce locomotor energy costs.
In the first study to fully examine this theory among humans and adult chimpanzees, published online July 17 in the Proceedings of the National Academy of Sciences, researchers have found that human walking is around 75 percent less costly, in terms of energy and caloric expenditure, than quadrupedal and bipedal walking in chimpanzees.
That energy savings could have provided early hominids with an evolutionary advantage over other apes by reducing the cost of foraging for food.
Conducted by Herman Pontzer, Ph.D., assistant professor of Anthropology in Arts & Sciences at Washington University in St. Louis; Michael Sokol of University of California, Davis; and David Raichlen of University of Arizona, the study used treadmill trials to analyze walking energetics and biomechanics for adult chimpanzees and humans.
The only other research study on chimpanzee locomotor cost, conducted in 1973, used juvenile chimpanzees, which have different locomotor mechanics and costs than adults.
The team also examined the early hominin fossil record, which they found to include predicted changes consistent with lower energy cost- longer hind legs compared to body mass and structural changes to the pelvic bone allowing for more upright walking.
Analysis of these features in early fossil hominins, coupled with with analysis of bipedal walking in chimpanzees, indicate that bipedalism in early, ape-like hominins could indeed have been less costly than quadrupedal knucklewalking.
“Walking upright on two legs is a defining feature that makes us human,” said Pontzer. “It distinguishes our entire lineage from all other apes.





Public release date: Eurekalert ,16-Jul-2007.
http://www.eurekalert.org/pub_releases/2007-07/wuis-too071607.php
Contact: Herman Pontzer
hpontzer@wustl.edu
617-480-0118
Washington University in St. Louis

Friday, 3 August 2007

Ancestral footprints












The importance of the fossil footprints shows that early humans were bipedal as early as four million years ago. The Laetoli footprints were discovered in 1978, in a remote part of Tanzania by Andrew Hill, a paleontologist and professor at Yale University; working with Mary Leakey's research team.

Approximately four million years ago, a volcano erupted blanketing the landscape with volcanic ash. Following precipitation, the ash became like plaster; producing an ideal surface for footprint impressions of the numerous animals.In time the surface turned into a hard cement preserving its captured tell-tale signs .
A member of our early human species, Australopithecus afarensis, provided a record of their passing, the fossil footprints indicate two individuals, walking side by side.