The Americas were the last continents colonized by humans and the nature and timing of this colonization has been the subject of intense scientific research for over a century. The Mormon Church claims special knowledge within this field of scientific research. Most Mormons believe that native people in the Americas and Polynesia are largely (or at least partly) descended from Israelites. These views are largely based on the sacred writings Mormons possess, in particular the Book of Mormon, and numerous statements by church leaders, including all of its prophets, over many decades. As recently as March 2013 native Central American Mormons from Honduras were reassured by an apostle that they are the descendants of father Lehi, an Israelite who the Book of Mormon claims sailed to the Americas in 600BC.
Scientists studying Native American populations see no cultural or genetic connection between Old and New World populations. There is a broad consensus view among archaeologists, geologists and biologists, based on more than a century of excavating thousands of archaeological sites, that the New World was first populated at least fifteen thousand years ago, and possibly as early as twenty thousand years ago, by migrants from Asia. These people entered the Americas via a wide expanse of land—called Beringia—which connected northeastern Asia with northwestern North America during ice ages when sea levels were lower. These small groups of migrants soon exploited the richness of the “new world,” and their populations grew quickly and expanded across the North and South American continents over a few thousand years. There is widespread agreement among archaeologists that there is no evidence that the cultural developments unveiled in the archaeological record in the New World were in any way inspired by visitors or migrants from Africa, Europe, or Asia.The Asian origin of essentially all Native Americans was firmly established by the middle of the 20th century, using classical genetic markers such as blood groups and variation in other proteins (enzymes). During the last two decades, much higher resolution molecular studies have confirmed the Asian origin of Native Americans, the timing of migrations into the Americas and the routes these people took as they entered North and South America.
Scientists carrying out molecular studies have focused on two portions of human DNA that have simple patterns of inheritance. The majority of our DNA (carried on our chromosomes) is passed from generation to generation as complex rearrangements of parental DNA. In contrast mitochondrial DNA (mtDNA) is passed along maternal lines from mothers to their offspring, while Y chromosome DNA (YDNA) is passed from father to son (Figure 1.1). These uni-parentally inherited DNAs have been used extensively to build maternal or paternal links between related populations and to study the movement of human populations throughout the world.
The earliest immigrants to the Americas brought with them a subset of the maternal and paternal DNA lineages present in their Asian source populations. An excellent summary of the distribution of global mtDNA and YDNA lineages can be found here.
Mitochondrial and Y-chromosome DNA variation in the Americas indicates unambiguously that the ancestors of Native Americans originated in Asia. Virtually all modern Native Americans possess an mtDNA lineage that belongs to one of five founding lineage families (haplogroups), which are all present among native populations of Siberia. These maternal lineages have now been designated A, B, C, D and X (Figure 1.2; Brown et al. 1998; Schurr et al. 1990). Of these haplogroups, only X is present in both central Asian and European populations; however, the X haplogroup is large and diverse, and the particular X lineage (X2a) found in Native American populations represents a distinct branch on the Eurasian X lineage tree (Reidla et al. 2003).
The four major Native American founding lineages have been renamed A2, B2, C1, and D1 to distinguish them from closely related lineages in Asia.
A small proportion of mtDNA lineages found in indigenous peoples (<1%) are derived from recent non-native (European or African) admixture (Gonzales et al. 2003; Richards et al. 1996). The majority of these mtDNAs belong to lineage H, the most common mtDNA lineage family in European populations such as Spain and the United Kingdom (Figure 1.3.). The most common mtDNA lineage among Ashkenazi Jews is lineage K (Behar et al. 2004). Lineage L is the most common lineage in African populations.
Behar, D. M., Hammer, M. F. Garrigan, D., et al. (2004) MtDNA evidence for a genetic bottleneck in the early history of the Ashkenazi Jewish population. European Journal of Human Genetics. 12, 355-364.
Brown, M. D., Hosseini, S. H., Torroni, A. et al. (1998) MtDNA haplogroup X: An ancient link between Europe western Asia and North America? American Journal of Human Genetics 63, 1852–1861.
Gonzales, A. M., Brehm, A., Perez, J. A., et al. (2003) Mitochondrial DNA affinities at the Atlantic fringe of Europe. American Journal of Physical Anthropology. 120, 391-404.
Reidla, M., Kivisild, T. Metspalu, E. et al. (2003) Origin and diffusion of mtDNA haplogroup X. American Journal of Human Genetics 73, 1178–1190.
Richards, M., Côrte-Real, M. Forster, P. et al. (1996). "Paleolithic and Neolithic lineages in the European mitochondrial gene pool," American Journal of Human Genetics 59, 185-203.
Schurr, T. G., Ballinger, S. W. Gan, Y. Y. et al. (1990) Amerindian mitochondrial DNAs have rare Asian mutations at high frequencies, suggesting they are derived from 4 primary maternal lineages. American Journal of Human Genetics 46, 613–623.
Southerton, S. G. (2004) Losing a Lost Tribe: Native Americans, DNA and the Mormon Church. Salt Lake City, Signature Books.