Description

Mitochondrial haplogroup X is one of the rarest and most enigmatic of the founding lineages found in the Americas. X2 — the dominant subclade — shows a puzzling trans-oceanic distribution: it is found in West Eurasian populations (Druze 26%, Georgians 8%, Near Easterners 3–5%) and also among certain North American Native peoples, most notably the Ojibwe and other Algonquian-speaking groups (up to 25%). The absence of X in Siberian and East Asian populations — the expected stepping-stone for Beringian migration — makes its presence in North America one of the great unsolved mysteries of population genetics. The leading hypothesis is that X entered North America as part of the founding Beringian migration but has since been lost from Siberian populations.

Interesting Fact

The Druze of the Levant carry haplogroup X at frequencies up to 26% — the highest of any population on Earth — while some Ojibwe communities in North America also carry X at ~25%. These two populations are separated by thousands of kilometres with no intermediate carriers, making X's American presence one of the most debated puzzles in archaeogenetics.

Distribution by Ethnicity

Ethnic distributionRegionFrequencySample
DruzeNear East (Lebanon/Israel)
26%
n=120
OjibweAmericas (Great Lakes)
25%
n=60
GeorgiansCaucasus
8%
n=250
Algonquian peoples (average)Americas (Northeast)
7%
n=300
Near Easterners (average)Near East
4%
n=1000
Europeans (average)Europe
2%
n=5000

Tags

References

  1. Brown et al. (1998) — mtDNA haplogroup X: an ancient link between Europe/western Asia and North America? American Journal of Human Genetics 63(6), 1852–1861.
  2. Reidla et al. (2003) — Origin and diffusion of mtDNA haplogroup X. American Journal of Human Genetics 73(5), 1178–1190.
  3. Fagundes et al. (2008) — Mitochondrial population genomics supports a single pre-Clovis origin with a coastal route for the peopling of the Americas. American Journal of Human Genetics 82(3), 583–592.