1. ¹Unitat de Biologia Evolutiva, Departament de Ciències de la Salut i de la Vida, Universitat Pompeu Fabra, Barcelona 08003, Spain
2. ²Wellcome Trust Center for Human Genetics, University of Oxford, Headington, UK
3. ³Institute of Immunology, Academy of Sciences, Tashkent, Uzbekistan

Correspondence: Dr D Comas, Universitat Pompeu Fabra Unitat de Biologia Evolutiva, Doctor Aiguader 80 Barcelona, Catalonia 08003, Spain. Tel: +34 93 5422844; Fax: +34 93 5422802; E-mail: david.comas@upf.edu

⁴These authors contributed equally to the present study.

Received 28 July 2003; Revised 12 December 2003; Accepted 17 December 2003; Published online 11 February 2004.

Abstract

Mitochondrial DNA (mtDNA) lineages of 232 individuals from 12 Central Asian populations were sequenced for both control region hypervariable segments, and additional informative sites in the coding region were also determined. Most of the mtDNA lineages belong to branches of the haplogroups with an eastern Eurasian (A, B, C, D, F, G, Y, and M haplogroups) or a western Eurasian (HV, JT, UK, I, W, and N haplogroups) origin, with a small fraction of Indian M lineages. This suggests that the extant genetic variation found in Central Asia is the result of admixture of already differentiated populations from eastern and western Eurasia. Nonetheless, two groups of lineages, D4c and G2a, seem to have expanded from Central Asia and might have their Y-chromosome counterpart in lineages belonging to haplotype P(xR1a). The present results suggest that the mtDNA found out of Africa might be the result of a maturation phase, presumably in the Middle East or eastern Africa, that led to haplogroups M and N, and subsequently expanded into Eurasia, yielding a geographically structured group of external branches of these two haplogroups in western and eastern Eurasia, Central Asia being a contact zone between two differentiated groups of peoples.