Maternal variation in Huichol and Mixtec populations from Mexico

1.4 World mtDNA haplogroups
The most common way to represent phylogenetic relations is to reconstruct phylogenetic trees
of mtDNA lineages. In the root of the global mtDNA tree is the „mitochondrial Eve“, who
lived approximately 150,000-200,000 years before present (ybp) (Ingman et al., 2001; Soares
et al., 2009), which is very close to the age of the earliest modern humans estimated from
fossil data ~195,000 ybp (McDougall et al., 2005). This MRCA gave rise to exclusively
African major haplogroups L0-6. Only one of them, haplogroup L3, is shared by Africans
with the rest of the world (Vigilant et al., 1991; Chen YS et al., 1995; Brown, 1980). In
addition to other branches, In addition to others branches, L3 gave rise to macro-haplogroups
M, N, and N subgroup R, which are ancestors of all non-African mtDNA lineages. The
founding ages of the corresponding root types of M, N and R clades are very similar, about
60,000 years (Macaulay et al., 2005), raising the possibility that M and N haplogroups are
derived from a single African migration, which took place ~ 65,000-70,000 ybp from eastern
Africa (Forster, 2001; Soares et al., 2009;). The haplogroup N (including R) has spread all
over Eurasia, in contrast to haplogroup M, which is found in Eastern Eurasia but is virtually
absent in Europe (Metspalu et al., 2004). Macro-haplogroup M gave rise to different M
haplogroups (M1-M25) and to haplogroups D, C, E, G, Q and Z. Macro-haplogroup N gave
rise to haplogroups A, I, O, S, W, X and Y. From haplogroup R derive haplogroups B, F, J, H,
K, P, T, HV, V, and U.
As confirms the archaeological data, already by 40,000 ybp modern humans were in southern
Siberia and by 30,000 ybp have spread to the arctic Siberia (Goebel, 1999; Pitulko et al.,
2004). The data when humans moved from Asia to America is still debatable, but this could
happen between 30,000 and 13,000 ybp (Goebel et al., 2008).
1.5 Native American mtDNA haplogroups
America was the last continent reached by anatomically modern humans. In early studies,
based on RFLP analysis and through sequencing of the HVS-I region, 4 distinct haplogroup
clusters were recognized, initially named A, B, C and D (Schurr et al., 1990; Torroni et al.,
1993); the X haplogroup was identified a few years later (Brown et al., 1998). Today they are
termed as A2, B2, C1, D1 and X2a haplogroups (Achilli et al., 2008; Perego et al., 2009;
Tamm et al., 2007). The study of complete Amerindian mtDNA sequences has allowed
investigators to examine mtDNA variation in the Americas with much greater resolution.
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