Thursday, April 7, 2016

Discovery of New Neandertal DNA Reveals More about Human Evolution

Fossils recovered in Sima de los Huesos, Spain contain new DNA of the Neandertal genome. In addition, this discovery of the new DNA places Neandertals living in Europe approximately 430,000 years ago. The DNA was discovered in a tooth and leg bone. Furthermore, the DNA recovered from the tooth and leg bone only match 1% of the existing genome of Neandertals. Therefore, the DNA recovered was used to compare a women Neandertal’s DNA and a Denisovan (believed to be a distant cousin of Neandertals and Homo sapiens) women’s DNA.  Homo heidelbergensis is believed to be the common ancestor of both Homo sapiens and Neandertals, so Denisovan DNA could be a missing link in human evolution. This comparison is vital because its results will help scientists discover the genetics of human evolution.
            After the comparison, a greater genetic mystery emerged. Since, the nuclear DNA (inherited from both parents to the child) matches Neandertal DNA. However, the mitochondrial DNA (inherited usually only from the mother) matches the Denisovan DNA.  This suggests that a genetic split or divergence occurred approximately 430,000 years between Neandertals and Denisovans. Furthermore, the new genetic data implies that genetic split between Neandertals and Homo sapiens occurred even sooner, approximately 650,000 years ago. However, the new genetic evidence does not prove or disprove that Homo heidelbergensis is a common ancestor of the three species. As the most likely explanation for the difference in DNA is inbreeding among the different species.
Original Source:  https://www.sciencenews.org/article/ancient-dna-reveals-who-spain%E2%80%99s-%E2%80%98pit-bones%E2%80%99-cave?mode=topic&context=87&tgt=nr
Additional Readings: http://www.nytimes.com/2016/02/23/science/ancient-humans-may-have-left-a-genetic-mark-on-neanderthals.html?_r=0

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