If you have European or Asian ancestry, 1 to 4% of your entire DNA sequence may come from Neanderthals, resulting from interbreeding between modern humans and Neanderthals. This finding comes from analyses of the Neanderthal genome – the DNA sequences of the closest evolutionary relative to modern humans.
This article appeared in the Spring 2013 issue of Current Exchange Magazine.
In May of 2010, a group of researchers led by Svante Pääbo of the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany published 60% of the Neanderthal genome. The genome was reconstructed from three female Neanderthal bone samples found in the Vindija Cave in Croatia.
Researchers compared the human and Neanderthal genomes to identify genes unique to modern humans. Some of the genes found only in humans are important for skin development, metabolism, and cognitive abilities. Specifically, differences in the RUNX2 gene may explain morphological differences in the brain and the upper body between humans and Neanderthals.
For many years, the question of whether modern humans and Neanderthals mated has been intensely debated. Coming as a surprise to the researchers, portions of the human genome resemble parts of the Neanderthal genome. In particular, sequences from humans of non-African descent (European, Asian, Papaun) are found to be more similar to Neanderthals than to Africans.
Recently, Sriram Sankararaman and David Reich of the Department of Genetics at Harvard Medical School in Boston, Massachusetts and co-author Pääbo published a study estimating that the last interbreeding events between Europeans and Neanderthals most likely occurred 47,000–65,000 years ago. This recent time frame counters the hypothesis that the sequences shared between non-Africans and Neanderthals may have come from a more ancient ancestor.
With advances in sequencing and analyzing ancient DNA, more studies will address the question of interbreeding between modern humans and Neanderthals and elucidate the genes that make humans unique.