The human colonization of the
Americas: population genetics
Simon G. Southerton
Published Online: 4 FEB 2013
"The Encyclopedia of Global Human Migration provides a complete exploration of the movements of human populations from prehistory to the present day. It includes thematic interpretations and theories of migration, as well as the significant contemporary scientific discoveries and scholarly interpretations that have reshaped the way historians and social scientists analyze and map the past."
Volume 1 is dedicated exclusively to prehistoric migration. My chapter documents the genetic evidence for the colonization of the Americas, while chapter 8 by David Meltzer examines the archaeological evidence. The two chronologies (archaeological and genetic) are generally in good agreement. Other chapters that may interest folk include Chapter 41 Polynesia, East and South, including transpacific migration; Chapter 44 North America: Eskimo-Aleut linguistic history and Chapter 45 North America: Paleoeskimo and Inuit archaeology.
Migration to Beringia“The earliest immigrants to the Americas brought with them a subset of the maternal and paternal DNA lineages present in their Asian source populations. … Virtually all modern Native Americans possess an mtDNA lineage that belongs to one of five founding haplogroups, which are all present among native populations of Siberia. These maternal lineages have been designated A, B, C, D, and X. Of these haplogroups, only X is present in both central Asian and European populations; however, the X haplogroup is large and diverse, and the X lineage (X2a) found in Native American populations represents a distinct branch on the Eurasian X lineage tree.”
“Interestingly, these late Pleistocene migratory parties included domesticated dogs, as mtDNA sequences isolated from ancient dog remains from Latin America and Alaska are most closely related to the DNA lineages present in Old World dogs.”
Migration into North and South America"Analyses of mtDNA subclades within haplogroups has been particularly useful for exploring the nature of Native American migrations from Beringia into the remainder of the Americas. Three subclades of mtDNA subhaplogroup C1 are widely distributed among North, Central, and South American Indians... The coalescence estimates for them is 16.6–11.2 kya, which suggests that the colonization of the Americas south of the continental ice sheets may have occurred after the LGM. A date of 16–17 kya, as suggested by the genetic evidence, is in agreement with recent archaeological discoveries (e.g. from Monte Verde in Chile and Meadowcroft in Pennsylvania) that predate Clovis lithic sites in North America" (See Figure below).
Controversial migration theories“Molecular genetics discoveries are contributing important new data to often heated debates surrounding less widely supported hypotheses of the settlement of the Americas. ...
There is currently little evidence that Native Americans migrated beyond the Americas into the Pacific or that Polynesians settled in large numbers in the Americas. A distinctive “Polynesian lineage” belonging to the mtDNA B haplogroup, which is shared by almost all extant Polynesians, has not been detected among Native American populations. There is currently no genetic evidence that peoples from Melanesia, Polynesia, Australia, Africa, Europe, China, or the Middle East contributed significantly to the pre-historic Native American gene pool. The molecular genetic data thus offer little support for settlement theories at the fringe of mainstream anthropology and archaeology. Interestingly, in response to molecular research, the Mormon Church (Church of Jesus Christ of Latter-day Saints) recently changed its belief that Israelites were the “principal ancestors” of Native Americans to a still overly hopeful qualification that they were “among the ancestors of the American Indians”. However, the question of whether there could have been small admixtures from other parts of the world is frequently raised by journalists, maverick anthropologists, and revisionist historians."