vineri, 25 aprilie 2008

That's how we spread

That's how we spread in the beginning. From Africa to Africa, then from Africa to the rest of the world.

Read in National Geographics the layman version of the story. Or in The Economist: Before the Exodus.

Read / download here the academic version, from The American Journal of Human Genetics.



Figure 1. Simplified Human mtDNA Phylogeny

Source: Behar et al., The Dawn of Human Matrilineal Diversity, The American Journal of Human Genetics (2008), doi:10.1016/j.ajhg.2008.04.002





Figure 2. Maternal Gene Flow within Africa


Source: Behar et al., The Dawn of Human Matrilineal Diversity, The American Journal of Human Genetics (2008), doi:10.1016/j.ajhg.2008.04.002


Quote for Figure 2:
The gradual maternal movements suggested by the first (A) and second (B) hypotheses are denoted by the ascending numerical labels. A
gradient colorization system is used to illustrate the timing of the events.

The temporal direction and timing of the arrows and expansion
waves are general and should not be treated as firm migratory paths.

(A) An initial prolonged colonization (brown) by anatomically modern humans (1) is followed by a dispersal wave (green) of a fracture of
the population (2) and the localization of L0d and L0k to southern Africa (3).

(B) An early Homo sapiens division in a hypothetical migration zone (1) resulted in two separately evolving populations (2) and the
localization of L0 (green) in southern Africa and L105 (red) in eastern Africa.

A subsequent dispersal event of the L0abf subset from
the southern population and its mergence with the eastern population (brown) is suggested (3), resulting in the former population composed only of L0d and L0k and the latter composed of L105 and L0abf.

Later dispersal waves from the eastern African population parallels the beginning of African LSA approximately 70,000 ybp (4). Rapid
migrations during the LSA (5) brought descendants of the eastern African population into repeated contact with the southern population, peaking during the Bantu expansion (6).

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