Mapping the Neandertal Genome

         Last week in class, I mentioned the 2010 discovery that humans and Neandertals share a significant portion of DNA, accomplished through the means of inter-breeding. This topic helps to shape the way that we as humans view ourselves, our ancestors, and our place within our evolutionary genus. When reading this blog, think of the class discussion titled, Race and science, materiality and social construction.

        When the first fossilized remains of Homo Neanderthalensis, or neandertal were found in Germany in 1856, the world at large had not yet been exposed to the concepts of evolution or natural selection. Discovered just three years prior to the release of Darwin’s On the Origin of Species, the species Neandertal became the first of many species (including humans) to be classified under the genus homo. Evidence has shown, through the mapping of multiple genomes of Neandertals, and comparing the findings with multiple humans, that human and Neandertal DNA is 99.7% identical; leading to the definitive conclusion that the two species must have inter-breed. These findings indicate that Neandertal DNA which remains in modern humans enabled us to adapt much better to the cooler climate of Eurasia.

       The story of human and Neandertal inter-breeding is a story that begins in Africa; some 400,000 years ago, the species neandertal diverged from the same primate line that led to present day humans. The ancestors of Neandertals migrated north into Eurasia and became a geographically isolated species, where they “evolved independently from the line that became modern humans in Africa” (Mullikin, P.1). When modern humans arrived in Eurasia some 80,000 years ago, the humans inter-breed with the Neandertals who had evolved into a species well-adapted to survive the cold and hostile conditions of the time. This led to an evolutionary breakthrough for the survival of humans in Eurasia; the newly inherited genes helped our species adapt to the cold climate and prosper.  

        This ground-breaking discovery was made possible by a team of geneticists from across the globe; including researchers from the National Human Genome Research Institute (NHGRI). They first removed the DNA from the bones of three separate Neandertal fossils, who lived about 40,000 years ago in Europe. Next, the researchers compared this DNA to that of present-day humans from China, France, Papua New Guinea, southern Africa, and western Africa. According to NHGRI director Eric Green, Ph.D., “you must appreciate that this international team has produced a draft sequence of a genome that existed 400 centuries ago. Their analysis shows the power of comparative genomics and brings new insights to our understanding of human evolution” (Mullikin, P.1).

        As Dr. Green has suggested, the Neandertal study has revealed a great deal about the process of human evolution. The data suggests that the evolution of hominids did not progress in a straight line as once thought (picture the morphing from monkey to human diagram we have probably all seen). Rather, the data suggests that evolution is a “messier process, with emerging species merging back into the lines from which they diverged” (Mullikin, P.2).

For more information, please visit: 

National Institutes of Health

Nature News

 

 

 

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