title: The Expansion of mtDNA Haplogroup L3 within and out of Africa.
abstract: Although fossil remains show that anatomically modern humans dispersed out of Africa into the Near East ∼100 to 130 ka, genetic evidence from extant populations has suggested that non-Africans descend primarily from a single successful later migration. Within the human mitochondrial DNA (mtDNA) tree, haplogroup L3 encompasses not only many sub-Saharan Africans but also all ancient non-African lineages, and its age therefore provides an upper bound for the dispersal out of Africa. An analysis of 369 complete African L3 sequences places this maximum at ∼70 ka, virtually ruling out a successful exit before 74 ka, the date of the Toba volcanic supereruption in Sumatra. The similarity of the age of L3 to its two non-African daughter haplogroups, M and N, suggests that the same process was likely responsible for both the L3 expansion in Eastern Africa and the dispersal of a small group of modern humans out of Africa to settle the rest of the world. The timing of the expansion of L3 suggests a link to improved climatic conditions after ∼70 ka in Eastern and Central Africa rather than to symbolically mediated behavior, which evidently arose considerably earlier. The L3 mtDNA pool within Africa suggests a migration from Eastern Africa to Central Africa ∼60 to 35 ka and major migrations in the immediate postglacial again linked to climate. The largest population size increase seen in the L3 data is 3-4 ka in Central Africa, corresponding to Bantu expansions, leading diverse L3 lineages to spread into Eastern and Southern Africa in the last 3-2 ka.
authors.affiliation: IPATIMUP (Instituto de Patologia e Imunologia Molecular da Universidade do Porto), Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Soares
authors.forename: Farida
authors.initials: F
authors.lastname: Alshamali
authors.forename: Joana B
authors.initials: JB
authors.lastname: Pereira
authors.forename: Verónica
authors.initials: V
authors.lastname: Fernandes
authors.forename: Nuno M
authors.initials: NM
authors.lastname: Silva
authors.forename: Carla
authors.initials: C
authors.lastname: Afonso
authors.forename: Marta D
authors.initials: MD
authors.lastname: Costa
authors.forename: Eliska
authors.initials: E
authors.lastname: Musilová
authors.forename: Vincent
authors.initials: V
authors.lastname: Macaulay
authors.forename: Martin B
authors.initials: MB
authors.lastname: Richards
authors.forename: Viktor
authors.initials: V
authors.lastname: Cerny
authors.forename: Luísa
authors.initials: L
authors.lastname: Pereira
mesh_terms: D000349:Africa; D001483:Base Sequence; D001499:Bayes Theorem; D044383:Black People / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004641:Emigration and Immigration / Q000266:history*; D019143:Evolution, Molecular; D006239:Haplotypes / Q000235:genetics*; D049690:History, Ancient; D006801:Humans; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography; D011156:Population Density; D011157:Population Dynamics; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial