Copyright © 2008 The American Society of Human Genetics. All rights reserved.
The American Journal of Human Genetics, Volume 82, Issue 4, 883-894, 20 March 2008
doi:10.1016/j.ajhg.2008.01.017
Article
Analysis of Genomic Admixture in Uyghur and Its Implication in Mapping Strategy
Shuhua Xu1, 2, Wei Huang3, Ji Qian2 and Li Jin1, 2, 
, 
1 Chinese Academy of Sciences and Max Planck Society (CAS-MPG) Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
2 Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology and Center for Evolutionary Biology, School of Life Sciences and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, China
3 Chinese National Human Genome Center at Shanghai, Shanghai 201203, China
Corresponding authorAbstract
The Uyghur (UIG) population, settled in Xinjiang, China, is a population presenting a typical admixture of Eastern and Western anthropometric traits. We dissected its genomic structure at population level, individual level, and chromosome level by using 20,177 SNPs spanning nearly the entire chromosome 21. Our results showed that UIG was formed by two-way admixture, with 60% European ancestry and 40% East Asian ancestry. Overall linkage disequilibrium (LD) in UIG was similar to that in its parental populations represented in East Asia and Europe with regard to common alleles, and UIG manifested elevation of LD only within 500 kb and at a level of 0.1 < r2 < 0.8 when ancestry-informative markers (AIMs) were used. The size of chromosomal segments that were derived from East Asian and European ancestries averaged 2.4 cM and 4.1 cM, respectively. Both the magnitude of LD and fragmentary ancestral chromosome segments indicated a long history of Uyghur. Under the assumption of a hybrid isolation (HI) model, we estimated that the admixture event of UIG occurred about 126 [107∼146] generations ago, or 2520 [2140∼2920] years ago assuming 20 years per generation. In spite of the long history and short LD of Uyghur compared with recent admixture populations such as the African-American population, we suggest that mapping by admixture LD (MALD) is still applicable in the Uyghur population but ∼10-fold AIMs are necessary for a whole-genome scan.
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