Neanderthals Inside Us
Biologists have recently compiled a detailed analysis of the Neanderthal
genetic sequence and have found that their imprint has been left on the
human genome--evidence of mating between the two species.
By extracting the fragments of Neanderthal DNA from fossil bones, and deciphering 60 percent of the genome and comparing it with the genome of present day humans, the team of biologists concluded that "1 to 4 percent of the genome of non-Africans today is derived from Neanderthals."
According to evolutionary biologists and physical anthropologists, the two species split around 600,000 years ago, and Neanderthals were simultaneously on the scene until about 30,000 years ago. According to the biologists, the interbreeding between species "does not seem to have played a great role in human evolution." The evolution in cognition and bone structure that differentiated modern humans from Neanderthals has only been identified with about 100 genes that contributed to the evolution of modern humans since the divide.
Now a group of biologists believe they have confirmed the interbreeding
through evidence in the genome. We know that the species were
simultaneously on the scene "from 44,000 years ago when modern humans
first entered Europe to 30,000 years ago when the last Neanderthals fell
extinct." For years archaeologists have been looking for the so-called
"missing link" amongst our evolutionary ancestry--concrete
evidence of the interbreeding of these two species helps define that
link, while simultaneously muddling our history.
Due to the contamination of human DNA and Neanderthal DNA that often happens when examining such fossils, the data is heavily reliant on statistical analysis that have archaeologists questioning the integrity of the data. Though new precautions were taking to successfully analysis some data, cross-referencing with followup analysis will still need to be taken to make the data text-book ready.
What this interbreeding theory suggests is that all human populations today draw from the same gene pool that existed a mere 50,000 years ago, putting to challenge the "strong-out of-Africa hypothesis that everyone comes from the same population." This would mean that "Neanderthals interbred only with non-Africans, the people who left Africa, which would mean that non-Africans drew from a second gene pool not available to Africans."
Once again we find ourselves reworking our notion of history and showing that we do not hold all the answers. Knowledge is in the eye of the beholder with the truth buried by the changing winds of time. The more we unearth, the more our minds expand and have to reestablish our foundation.
Image: "DNA" by Mark Cummins on Flickr courtesy of Creative Commons Licensing.