Article

Major genomic mitochondrial lineages delineate early human expansions

Department of Genetics, Faculty of Biology, University of La Laguna, Tenerife, 38271, Spain.
BMC Genetics (Impact Factor: 2.4). 02/2001; 2(1):13. DOI: 10.1186/1471-2156-2-13
Source: PubMed

ABSTRACT

The phylogeographic distribution of human mitochondrial DNA variations allows a genetic approach to the study of modern Homo sapiens dispersals throughout the world from a female perspective. As a new contribution to this study we have phylogenetically analysed complete mitochondrial DNA(mtDNA) sequences from 42 human lineages, representing major clades with known geographic assignation.
We show the relative relationships among the 42 lineages and present more accurate temporal calibrations than have been previously possible to give new perspectives as how modern humans spread in the Old World.
The first detectable expansion occurred around 59,000-69,000 years ago from Africa, independently colonizing western Asia and India and, following this southern route, swiftly reaching east Asia. Within Africa, this expansion did not replace but mixed with older lineages detectable today only in Africa. Around 39,000-52,000 years ago, the western Asian branch spread radially, bringing Caucasians to North Africa and Europe, also reaching India, and expanding to north and east Asia. More recent migrations have entangled but not completely erased these primitive footprints of modern human expansions.

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    • "Phylogeographic inference based solely on mtDNA has limita- tions [2], but information from single loci can provide meaningful constraints on models of human prehistory. In particular, the fact that hg M has never previously been found in Europe is generally interpreted as an important limitation for the proposed scenarios of non-African population dispersals [4, 7]. According to the most popular model [4], an early expansion occurred before the M and N diversification with a subsequent loss of M in only the population ancestral to Europeans. "
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    • "Phylogeographic inference based solely on mtDNA has limita- tions [2], but information from single loci can provide meaningful constraints on models of human prehistory. In particular, the fact that hg M has never previously been found in Europe is generally interpreted as an important limitation for the proposed scenarios of non-African population dispersals [4, 7]. According to the most popular model [4], an early expansion occurred before the M and N diversification with a subsequent loss of M in only the population ancestral to Europeans. "

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    • "Studies on maternal ancestry of several lineages based on mtDNA also allow to obtain complementary information concerning the origin of man in Africa and its dispersion on and from this continent. The model most accepted in the scientific community concerning this matter, and confirmed by mtDNA analysis, is known as Out of Africa theory [24]. This postulates that, after an initial expansion of populations from Africa to Eurasia, the different populations did not maintain contact, and evolved independently. "
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