Large Sections of Archaic DNA Identified in Modern Melanesians

SEATTLE, WASHINGTON—Evan Eichler of the University of Washington and his colleagues have identified two large pieces of ancient hominin DNA in people now living in Melanesia, according to a New Scientist report. All modern humans have 23 pairs of chromosomes made up of tightly coiled DNA containing many genes. The first section of ancient DNA found in modern Melanesians came from Denisovans, and consists of two duplicated sections on chromosome 16. In a duplication, the original gene is kept, while the duplicate may change. “A duplication is a type of mutation that lets you have your cake and eat it too,” Eichler explained. The second section, inherited from Neanderthals, consists of a deletion and a duplication on chromosome eight. Both of these chromosome changes seem to have been advantageous to modern humans, Eichler added, because they became more common in Melanesians over time. The genes may have helped modern humans adapt to different climates, foods, and diseases as they migrated. “I think the biggest challenge is proving the function,” he said. For more on research comparing hominin and modern human genomes, go to "Living Evidence."