Original Research Article
X-chromosomal genetic diversity and linkage disequilibrium patterns in Amerindians and non-Amerindian populations
Article first published online: 3 FEB 2011
Copyright © 2010 Wiley-Liss, Inc.
American Journal of Human Biology
Volume 23, Issue 3, pages 299–304, May/June 2011
How to Cite
Amorim, C. E. G., Wang, S., Marrero, A. R., Salzano, F. M., Ruiz-Linares, A. and Bortolini, M. C. (2011), X-chromosomal genetic diversity and linkage disequilibrium patterns in Amerindians and non-Amerindian populations. Am. J. Hum. Biol., 23: 299–304. doi: 10.1002/ajhb.21110
- Issue published online: 11 APR 2011
- Article first published online: 3 FEB 2011
- Manuscript Accepted: 14 SEP 2010
- Manuscript Revised: 8 SEP 2010
- Manuscript Received: 5 APR 2010
- Institutos do Milênio and Apoio a Núcleos de Excelência Programs
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul
Objectives: We report X-chromosomal linkage disequilibrium (LD) patterns in Amerindian (Kogi, Wayuu, and Zenu) and admixed Latin American (Central Valley of Costa Rica and Southern Brazilian Gaucho) populations.
Methods: Short tandem repeats (STRs) widespread along the X-chromosome were investigated in 132 and 124 chromosomes sampled from the Amerindian tribes and the admixed Latin American populations, respectively. Diversity indexes (gene diversity and average numbers of alleles per locus) were estimated for each population and the level of LD was inferred with an exact test.
Results: The Amerindian populations presented lower genetic diversity and a higher proportion of loci in LD than the admixed ones. Two haplotype blocks were identified in the X-chromosome, both restricted to the Amerindians. The first involved DXS8051 and DXS7108 in Xp22.22 and Xp22.3, while the second found only among the Kogi, included eight loci in a region between Xp11.4 and Xq21.1.
Conclusions: In accordance to previous work done with other populations, human isolates, such as Amerindian tribes, seem to be an optimal choice for the implementation of association studies due to the wide extent of LD which can be found in their gene pool. On the other hand, the low proportion of loci in LD found in both admixed populations studied here could be explained by events related to their history and similarities between the allele frequencies in the parental stocks. Am. J. Hum. Biol., 2011. © 2011 Wiley-Liss, Inc.