Neanderthal

Homo sapiens, Neanderthals & Denisovans; Did They Interbreed?

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Screen Shot 2015-10-27 at 9.40.20 PMRecent discoveries in DNA have shed light on the relationship of Homo sapiens and extinct hominids, Homo neanderthalensis and Denisova hominins. There is evidence to suggest that all three lived around the same time, and possibly in the same area (Krause et al., 2010)(Meyer et al., 2012). If these three groups lived close together, it should be possible to detect whether or not theyinterbred. If H. sapiens interbred with H. neanderthalensis and D. hominins, we should be able to find genetic evidence of this interbreeding in modern H. sapiens genomes. Using modern genetic examination (Gibbons, 2010), scientists have determined that H. sapiens did interbreed with both H. neanderthalensis (Green et al, 2010)(Hawks, 2013)(Meyer et al, 2012) and with D. hominins (Hawks, 2013)(Meyer et al, 2012).

Homo neanderthalensis fossils were first discovered in 1856 in Germany, and ever since, scientists have been exploring the relationship of Neanderthals to modern humans. (Gibbons, 2012) The first “draft sequence of the Neanderthal genome” was published in 2010 (Green, et al), and that has given us insight into the relationship of Neanderthal DNA to the DNA of modern humans. Using data obtained by the Human Genome Project (Intl Human Genome Sequencing Consortium, 2001), scientists can compare human and Neanderthal DNA in order to discover the genetic relationship between the two.  The evidence suggests that Neanderthals lived in both Europe and Asia before going extinct around 30,000 years ago (Green et al, 2010). However, many of the Neanderthals interbred with H. sapiens before going extinct. According to Green and colleagues (2010) andHawks (2013), modern humans living outside of Africa represent between 1% and 4% of ancestry from Neanderthal populations. It is possible, with modern genomic technology, for the average person to send a sample of her own DNA to a lab (ex: ‘23andMe’) and get results showing her ancestry. If she has European ancestry, it is possible that she will also have some small percentage of Neanderthal ancestry (Gibbons, 2012). These sorts of results would only be possible had the Neanderthals interbred with direct ancestors of modern humans. Not all of the evidence suggests that Neanderthals interbred with the ancestors of modern humans, however. A study showed that there were no contributions from Neanderthal mtDNA to modern human mtDNA from a specimen recovered from Mezmaiskaya Cave in the northern Caucasus. (Ovchinnikov, 2000) This is not necessarily contradictory data from the other studies; it shows that not all Neanderthal populations interbred with modern human populations.
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