User:Treetoes023/List of extinct languages of Europe

All of the Indigenous peoples of the Americas during the pre-Columbian era belonged to one of five mitochondrial DNA haplogroups: A, B, C, D, or X, specifically the sub-haplogroups A2, B2, C1b, C1c, C1d, D1, and X2a (with minor groups C4c, D2a, and D4h3a).

The common occurrence of the mtDNA Haplogroups A, B, C, and D among eastern Asian and Indigenous American populations has long been recognized, along with the presence of Haplogroup X. As a whole, the greatest frequency of the four Indigenous American associated haplogroups occurs in the Altai-Baikal region of southern Siberia. Some subclades of C and D closer to the Indigenous American subclades occur among Mongolian, Amur, Japanese, Korean, and Ainu populations. A 2023 DNA study found that "[i]n addition to previously described ancestral sources in Siberia, Australo-Melanesia, and Southeast Asia, ... northern coastal China also contributed to the gene pool of Native Americans" as well as that of Japanese people.

When studying human mitochondrial DNA haplogroup, the results indicated that Indigenous American haplogroups, including haplogroup X, are part of a single founding East Asian population. It also indicates that the distribution of mtDNA haplogroups and the levels of sequence divergence among linguistically similar groups were the result of multiple preceding migrations from Bering Straits populations.

X is one of the five mtDNA haplogroups found in Indigenous Americans. Native Americans mostly belong to the X2a clade, which has never been found in the Old World. According to Jennifer Raff, X2a probably originated in the same Siberian population as the other four founding maternal lineages.

Haplogroup X genetic sequences diverged about 20,000 to 30,000 years ago to give two sub-groups, X1 and X2. X2's subclade X2a occurs only at a frequency of about 3% for the total current Indigenous population of the Americas. However, X2a is a major mtDNA subclade in North America; among the Algonquian peoples, it comprises up to 25% of mtDNA types. It is also present in lower percentages to the west and south of this area — among the Sioux (15%), the Nuu-chah-nulth (11%–13%), the Navajo (7%), and the Yakama (5%). The predominant theory for sub-haplogroup X2a's appearance in North America is migration along with A, B, C, and D mtDNA groups, from a source in the Altai Mountains of central Asia. Haplotype X6 was present in the Tarahumara 1.8% (1/53) and Huichol 20% (3/15)

Sequencing of the mitochondrial genome from Paleo-Eskimo remains (3,500 years old) are distinct from modern Indigenous Americans, falling within sub-haplogroup D2a1, a group observed among today's Aleutian Islanders, the Aleut and Siberian Yupik populations. This suggests that the colonizers of the far north, and subsequently Greenland, originated from later coastal populations. Then began a genetic exchange in the northern extremes introduced by the Thule people (proto-Inuit) approximately 800–1,000 years ago. These final Pre-Columbian migrants introduced haplogroups A2a and A2b to the existing Paleo-Eskimo populations of Canada and Greenland, culminating in the modern Inuit.



A route through Beringia is seen as more likely than the Solutrean hypothesis. An abstract in a 2012 issue of the "American Journal of Physical Anthropology" states that "The similarities in ages and geographical distributions for C4c and the previously analyzed X2a lineage provide support to the scenario of a dual origin for Paleo-Indigenous Americans. Taking into account that C4c is deeply rooted in the Asian portion of the mtDNA phylogeny and is indubitably of Asian origin, the finding that C4c and X2a are characterized by parallel genetic histories definitively dismisses the controversial hypothesis of an Atlantic glacial entry route into North America."

Another study, also focused on the mtDNA (which is inherited through only the maternal line), revealed that the Indigenous people of the Americas can trace their maternal ancestry back to a few founding lineages from East Asia, which would have arrived by way of the Bering Strait. According to this study, it is probable that the ancestors of the Indigenous Americans would have remained for a time in the region of the Bering Strait, after which there would have been a rapid movement of settling of the Americas, taking the founding lineages to South America.

According to a 2016 study, focused on mtDNA lineages, "a small population entered the Americas via a coastal route around 16.0 ka, following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations. Following a rapid movement throughout the Americas, limited gene flow in South America resulted in a marked phylogeographic structure of populations, which persisted through time. All of the ancient mitochondrial lineages detected in this study were absent from modern data sets, suggesting a high extinction rate. To investigate this further, we applied a novel principal components multiple logistic regression test to Bayesian serial coalescent simulations. The analysis supported a scenario in which European colonization caused a substantial loss of pre-Columbian lineages".