The Ghost in the Genome: Neanderthal Introgression, Epigenetics, and Human Disease
Modern humans carry a biological inheritance that predates our own species' dominance. Between 1% and 4% of the genomes of non-African populations are derived from Neanderthals, the result of interbreeding events that occurred roughly 50,000 to 60,000 years ago. While some of these archaic genetic variants provided evolutionary advantages such as adaptations to colder climates or new pathogens this "introgression" has a darker side. Today, these ancient snippets of DNA are increasingly linked to a spectrum of modern ailments, from autoimmune disorders to depression and schizophrenia. Emerging research suggests that the bridge between these ancient sequences and modern disease is often built by epigenetics. The Legacy of Introgression When Homo sapiens migrated out of Africa, they encountered Neanderthals who had already spent hundreds of thousands of years adapting to the Eurasian environment. Through interbreeding, humans "borrowed" genetic adaptati...