The genetic history of the Indigenous peoples of the Americas is divided into two distinct periods: the initial peopling of the Americas from about 20,000 to 14,000 years ago (20–14 kya), and European contact, after about 500 years ago. The first period of the genetic history of Indigenous Americans is the determinant factor for the number of genetic lineages, zygosity mutations, and founding haplotypes present in today's Indigenous American populations.
Indigenous American populations descend from and share ancestry with an Ancient East Asian lineage which diverged from other East Asian peoples prior to the Last Glacial Maximum (26–18 kya). They also received geneflow from Ancient North Eurasians, a distinct Paleolithic Siberian population with deep affinities to both "European hunter-gatherers" (e.g. Kostenki-14) and "Basal East Asians" (e.g. Tianyuan man). They later dispersed throughout the Americas after about 16,000 years ago (exceptions being the Na-Dene and Eskimo–Aleut speaking groups, which are derived partially from Siberian populations which entered the Americas at a later time).
