Diversity matters

Science Daily:

Human migration from Africa to Europe more than 30,000 years ago appears to have left a mark on the genes of Europeans today.

A Cornell-led study, reported in the Feb. 21 issue of the journal Nature, compared more than 10,000 sequenced genes from 15 African-Americans and 20 European-Americans. The results suggest that European populations have proportionately more harmful variations, though it is unclear what effects these variations actually may have on the overall health of Europeans.

Computer simulations suggest that the first Europeans comprised small and less diverse populations. That would have allowed mildly harmful genetic variations within those populations to become more frequent over time, the researchers report.

Egypt's first agricultual community

Science Daily:

Archaeologists from UCLA and the University of Groningen (RUG) in the Netherlands have found the earliest evidence ever discovered of an ancient Egyptian agricultural settlement, including farmed grains, remains of domesticated animals, pits for cooking and even floors for what appear to be dwellings.

The findings, which were unearthed in 2006 and are still being analyzed, also suggest possible trade links with the Red Sea, including a thoroughfare from Mesopotamia, which is known to have practiced agriculture 2,000 years before ancient Egypt.

"By the time of the Pharaohs, everything in ancient Egypt centered around agriculture," said Willeke Wendrich, the excavation's co-director and an associate professor of Near Eastern languages and cultures at UCLA. "What we've found here is a window into the development of agriculture some 2,000 years earlier. We hope this work will help us answer basic questions about how, why and when ancient Egypt adopted agriculture."

Waiting at the gate

Science Daily:

The human journey from Asia to the New World was interrupted by a 20,000 -year layover in Beringia, a once-habitable region that today lies submerged under the icy waters of the Bering Strait. Furthermore, the New World was colonized by approximately 1,000 to 5,000 people - a substantially higher number than the 100 or fewer individuals of previous estimates.

The developments, to be reported by University of Florida Genetics Institute scientists in PloS One, help shape understanding of how the Americas came to be populated - not through a single expansion event that is put forth in most theories, but in three distinct stages separated by thousands of generations.

"Our model makes for a more interesting, complex scenario than the idea that humans diverged from Asians and expanded into the New World in a single event," said Connie Mulligan, Ph.D., an associate professor of anthropology at the College of Liberal Arts and Sciences and assistant director of the UF Genetics Institute. "If you think about it, these people didn't know they were going to a new world. They were moving out of Asia and finally reached a landmass that was exposed because of lower sea levels during the last glacial maximum, but two major glaciers blocked their progress into the New World. So they basically stayed put for about 20,000 years. It wasn't paradise, but they survived. When the North American ice sheets started to melt and a passage into the New World opened, we think they left Beringia to go to a better place."

UF scientists analyzed DNA sequences from Native American, New World and Asian populations with the understanding that modern DNA is forged by an accumulation of events in the distant past, and merged their findings with data from existing archaeological, geological and paleoecological studies.

The result is a unified, interdisciplinary theory of the "peopling" of the New World, which shows a gradual migration and expansion of people from Asia through Siberia and into Beringia starting about 40,000 years ago; a long waiting period in Beringia where the population size remained relatively stable; and finally a rapid expansion into North America through Alaska or Canada about 15,000 years ago.

Neanderthals were going mobile

Science Daily:

A 40,000-year-old tooth has provided scientists with the first direct evidence that Neanderthals moved from place to place during their lifetimes. In a collaborative project involving researchers from the Germany, the United Kingdom, and Greece, Professor Michael Richards of the Max Planck institute for Evolutionary Anthropology in Leipzig, Germany and Durham University, UK, and his team used laser technology to collect microscopic particles of enamel from the tooth. By analysing strontium isotope ratios in the enamel - strontium is a naturally occurring metal ingested into the body through food and water - the scientists were able to uncover geological information showing where the Neanderthal had been living when the tooth was formed.

The tooth, a third molar, was formed when the Neanderthal was aged between seven and nine. It was recovered in a coastal limestone cave in Lakonis, in Southern Greece, during an excavation directed by Dr Eleni Panagopoulou of the Ephoreia of Paleoanthropology and Speleology (Greek Ministry of Culture). The strontium isotope readings, however, indicated that the enamel formed while the Neanderthal lived in a region made up of older volcanic bedrock. The findings could help answer a long-standing debate about the mobility of the now extinct Neanderthal species.

Some researchers argue that Neanderthals stayed in one small area for most of their lives; others claim their movements were more substantial and they moved over long distances; and others say they only moved within a limited area, perhaps on a seasonal basis to access different food sources.

Professor Richards said: "Strontium from ingested food and water is absorbed as if it was calcium in mammals during tooth formation. Our tests show that this individual must have lived in a different location when the crown of the tooth was formed than where the tooth was found. The evidence indicates that this Neanderthal moved over a relatively wide range of at least 20 kilometres or even further in their lifetime. Therefore we can say that Neanderthals did move over their lifetimes and were not confined to limited geographical areas."

Cousins

Science Daily:

New research shows that people with blue eyes have a single, common ancestor. A team at the University of Copenhagen have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today.

“Originally, we all had brown eyes”, said Professor Eiberg from the Department of Cellular and Molecular Medicine. “But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a “switch”, which literally “turned off” the ability to produce brown eyes”. The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The “switch”, which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris – effectively “diluting” brown eyes to blue. The switch’s effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour – a condition known as albinism.

Not fast enough

Los Angeles Times:

The pace of human evolution has been increasing at a stunning rate since our ancestors began spreading through Europe, Asia and Africa 40,000 years ago, quickening to 100 times historic levels after agriculture became widespread, according to a study published today.

By examining more than 3 million variants of DNA in 269 people, researchers identified about 1,800 genes that have been widely adopted in relatively recent times because they offer some evolutionary benefit.

Until recently, anthropologists believed that evolutionary pressures on humans eased after the transition to a more stable agrarian lifestyle. But in the last few years, they realized the opposite was true -- diseases swept through societies in which large groups lived in close quarters for a long period.

Altogether, the recent genetic changes account for 7% of the human genome, according to the study published in the Proceedings of the National Academy of Sciences.

Why We Walk

Science Daily:

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.

Eternal Love

ANSA:

A series of tests has begun on a pair of embracing skeletons, which have lain in one another's arms for 6,000 years.

The Stone Age skeletons of a young man and woman were uncovered at the start of February during digs in Valdaro, an area not far from the central Italian city of Mantua.

The remains have now been carefully unearthed, without separating them, and taken to laboratories in the northern city of Como, where scientists will test the initial conclusions drawn by archaeologists.