Presentation: Our Archaic Human Ancestors
Speaker: Sharon Browning, Ph.D., Research Professor of Biostatistics, University of Washington
Abstract: Archaic human populations, such as Neanderthals, split off from the ancestors of modern humans hundreds of thousand years ago. Around fifty thousand years ago, as modern humans expanded their geographical range, they encountered and admixed with archaic human populations. Recent sequencing of DNA from Neanderthal fossils showed that Eurasians carry several percent of their DNA from Neanderthal ancestors. It is clear that other archaic humans also contributed to the human lineage. In particular, Denisovans, an archaic human population that lived in Asia, contributed significantly to the ancestry of Papuans and, to a lesser extent, to the ancestry of Asians. My analysis of human genetic data from the 1000 Genomes Project revealed that there were at least two occurrences of admixture between Denisovans and modern humans: one occurrence led to significant Denisovan ancestry in Papuans and a small fraction of Denisovan ancestry throughout Asia, and the other occurrence contributed a small fraction of the ancestry of modern East Asians. I will present this result and the statistical methodology that was used to obtain it.