IngentaConnect Compound haplotypes at Xp11.23 and human population growth in Eur...

Authors: S. Alonso; J. A. L. Armour¹

Source: Annals of Human Genetics, Volume 68, Number 5, September 2004 , pp. 428-437(10)

Abstract:

Summary

To investigate patterns of diversity and the evolutionary history of Eurasians, we have sequenced a 2.8 kb region at Xp11.23 in a sample of African and Eurasian chromosomes. This region is in a long intron of CLCN5 and is immediately flanked by a highly variable minisatellite, DXS255, and a human-specific Ta0 LINE. Compared to Africans, Eurasians showed a marked reduction in sequence diversity. The main Euro-Asiatic haplotype seems to be the ancestral haplotype for the whole sample. Coalescent simulations, including recombination and exponential growth, indicate a median length of strong linkage disequilibrium, up to sim

9kb for this area. The K_a/K_s ratio between the coding sequence of human CLCN5 and its mouse orthologue is much less than 1. This implies that the region sequenced is unlikely to be under the strong influence of positive selective processes on CLCN5, mutations in which have been associated with disorders such as Dent's disease. In contrast, a scenario based on a population bottleneck and exponential growth seems a more likely explanation for the reduced diversity observed in Eurasians. Coalescent analysis and linked minisatellite diversity (which reaches a gene diversity value greater than 98% in Eurasians) suggest an estimated age of origin of the Euro-Asiatic diversity compatible with a recent out-of-Africa model for colonization of Eurasia by modern Homo sapiens.

Keywords: DXS255; LINE; human evolution; coalescent; Xp11.23; Linkage Disequilibrium

Document Type: Research article

DOI: 10.1046/j.1529-8817.2003.00115.x

Affiliations: 1: Institute of Genetics, University of Nottingham, Nottingham NG7 2UH, UK

You have access to the full text article on a website external to Ingentaconnect.

Please click here to view this article on InterScience.

You may be required to register and activate access on InterScience before you can obtain the full text. If you have any queries please contact onlinehelp@oxon.blackwellpublishing.com

Compound haplotypes at Xp11.23 and human population growth in Eurasia