45,000 Year Old Bone Reveals Exact Timeline of Human-Neanderthal Mating

45,000 Year Old Bone Reveals Exact Timeline of Human-Neanderthal Mating

DNA from a 45,000 year old bone provides proof of a “universal” human and reveals an exact timeline of human-Neanderthal mating. A modern human femur found in a river bank in Siberia is the oldest bone identified as Homo sapiens that has provided enough genetic material to map a complete genome. The DNA has overturned some previous assumptions about man’s evolution.

A Russian artist was looking for mammoth tusks in Siberia when he found the femur. Nikolai Peristove turned the bone over to the Russian Academy of Sciences which identified it as modern human. Then the bone was dated by the University of Oxford and discovered to be 45,000 years old. Finally, the bone made its way to the Max Planck Institute in Leipzig Germany for a complete DNA analysis.

The original owner of the femur was named Ust’Ishm after a Siberian settlement it was found near. This male hunter is one of the earliest humans found in Eurasia. Paleoanthropologists Svante Paabo and Bence Viola have used their analysis of his DNA to create an increasingly accurate story of how modern humans spread through the world and how they interacted with other hominids.

Modern humans and Neanderthals shared a common ancestor 600,000 years ago, and then were believed to evolve separately. Neanderthals evolved in Europe and Homo sapiens in Africa. Scientific breakthroughs have allowed anthropologists to track DNA which has yielded the surprising discovery that not only did Neanderthals and humans walk the earth at the same time, they mated regularly with one another. The 45,000 year old bone reveals an exact timeline of human-Neanderthal mating.

All of today’s non-Africans have inherited about two percent of their DNA from Neanderthals. The difference of Ust’-Ishm is that the Neanderthal segments of DNA are much longer than today’s short and shuffled genes. The length of the segments indicates a recent mixing of Neanderthal and Homo sapien genomes. Ust’-Ishm’s DNA leads researchers to believe that interbreeding occurred between 50,000 and 60,000 years ago. Before mapping this genome, the timing for mating between the two species was uncertain. Anthropologists theorized it occurred between 37,000 and 86,000 years ago. Narrowing the time period for the mixing of genes allows researchers to paint a clearer picture of human development. Ust’-Ishm’s DNA reveals that his ancestors combined DNA between 7,000 and 13,000 years before he was born. The 50,000 to 60,000 window coincides with a major expansion of humans throughout Europe and Asia.

Archeologists have collected evidence of human habitation in India and the Middle East from as long as 100,000 years ago. Modern humans evolved solely in Africa for most of their history. Scientists supposed that Homo sapiens began their exodus from Africa about 100,000 years ago and steadily expanded their range to encompass the entire world. Ust’-Ishm’s bone casts doubt on this theory. More likely, humans migrated out of Africa in waves, with many of the early waves of modern humans dying out. The current ancestors of all Europeans and Asians left Africa as recently as 60,000 years ago. As this group spread they supplanted their contemporaries Homo erectus and the Neanderthals, who went extinct 40,000 years ago.

Ust’-Ishm’s people are genetically different from Africans, but also from Europeans and Asians. He seems to fit in a time period between the exodus from Africa but before the split into Europeans and Asians. Based on his genome, he is likely from a group that died out, but was a contemporary and very similar to the humans that gave rise to populations covering Eurasia and the Americas. These people had dark skin, distinct facial features and dark hair. For almost all of human evolution all non-Africans shared very similar characteristics.

DNA evidence has proven many theories about human development wrong. Humans did not differentiate 100,000 years ago simply because they began to move out of Africa to new locations. Rather, early people retained their genetics and appearance as they spread across the globe. Only after the Neolithic Revolution changed the human diet in parts of the world did the human species differentiate some characteristics. Before that time, there probably was a more universal human who combined all the traits of today’s races. Humans and Neanderthals provided the basis for this “universal” human.

Once more, genetic evidence shows that human evolution, migration and settlement were much more complex and convoluted than anthropologists previously theorized. It was not a straight line but a series of experiments with stops and starts. Somehow, the ancestors of today’s humans were able to figure out the survival game. The racial features that have influenced much of modern history and human interactions were probably nonexistent until very recently. DNA from a 45,000 year old bone provides proof of the universal human and reveals an exact timeline of human-Neanderthal mating.

By: Rebecca Savastio

Sources:

NY Times

Scientific American

BBC

Biosciencetechnology

 

One Response to "45,000 Year Old Bone Reveals Exact Timeline of Human-Neanderthal Mating"

  1. RURIGHT   October 25, 2014 at 4:29 pm

    How do they know the bones are 45,000 years old? What tool or algorithms did they use to come up with 45,000 years?

    Reply

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