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.

Genetic variation in Tunisia in the context of human diversity worldwide

“…Indeed, uniparental genetic data support the arrival of sub‐Saharans around 20,000 years ago according to Frigi et al (2010). Other studies show that the introduction of sub‐Saharan mtDNA lineages in North Africa is older than 30,000 YBP (Soares et al, 2012). The mixture between Iberian and sub‐Saharan Saharan populations was described in papers such as Periera et al (2010), but more studies are needed to substantiate that mixture.…”

Variability in the Middle Stone Age of Eastern Africa

“…4, top) suggests important behavioral changes during the later Pleistocene. All of these elements characterize sites of the regional LSA, imply a prolonged shift to LSA technologies, and suggest that the 70-35 ka interval of major population dispersals within and out of Africa (Soares et al 2012) was one characterized by important technological changes. Some of the artifact forms underlying this technological shift have been suggested as markers of out-of-Africa population dispersals to southern and eastern Asia (Mellars 2006b(Mellars , 2006c, although Neanderthal populations in Europe apparently independently invented similar elements during the same time interval (d 'Errico and Stringer 2011).…”

Mosaic maternal ancestry in the Great Lakes region of East Africa

“…Within Africa, a number of mtDNA lineages have been associated with various stages of the Bantu dispersals, including subsets of L0a Watson et al 1997), L1c (Batini et al 2007;Salas et al 2002), L2a Salas et al 2002), L3b (Salas et al 2002;Soares et al 2012;Watson et al 1997) and L3e (Bandelt et al 2001;Pereira et al 2001;Plaza et al 2004;Salas et al 2002;Soares et al 2012). Many of these are inferred to have spread from West-Central Africa, although some, e.g.…”

“…3), both of which highly informative, albeit pointing in different directions. Although rare, haplogroup L3h is present across Eastern Africa (Kivisild et al 2004;Poloni et al 2009;Soares et al 2012;Tishkoff et al 2007). It dates to ~55.1 ka (Soares et al 2014) with the two basal subclades L3h1 and L3h2 dating to ~47 ka (Behar et al 2012) and L3h2 to ~31 ka (from our HVS-I network).…”

“…This is reflected in a substantial Eurasian autosomal component in Eastern Africa, which is also evident to some extent in Kenya (Pagani et al 2012). Due to deep ancestry and the distribution of these lineages (Abu-Amero et al 2008;Brakez et al 2001;Černý et al 2008;Coudray et al 2009;Fernandes et al 2012;Kivisild et al 2004;Olivieri et al 2006;Rhouda et al 2009;Richards et al 2000;Richards et al 2003), none of the West Eurasian mtDNAs found in Uganda has a likely European source, for example resulting from the heavy European colonial involvement since the 1870s (Maxon 2009). One possibility is a Bronze-Age dispersal from the Near East accompanying the spread of Semitic languages (Kitchen et al 2009), consistent with an 18 inferred Levantine (rather than Arabian) source (Pagani et al 2012).…”