β-globin gene cluster haplotypes in ethnic minority populations of southwest China

Abstract

The genetic diversity and relationships among ethnic minority populations of southwest China were investigated using seven polymorphic restriction enzyme sites in the β-globin gene cluster. The haplotypes of 1392 chromosomes from ten ethnic populations living in southwest China were determined. Linkage equilibrium and recombination hotspot were found between the 5' sites and 3' sites of the β-globin gene cluster. 5' haplotypes 2 (+---), 6 (-++-+), 9 (-++++) and 3' haplotype FW3 (-+) were the predominant haplotypes. Notably, haplotype 9 frequency was significantly high in the southwest populations, indicating their difference with other Chinese. The interpopulation differentiation of southwest Chinese minority populations is less than those in populations of northern China and other continents. Phylogenetic analysis shows that populations sharing same ethnic origin or language clustered to each other, indicating current β-globin cluster diversity in the Chinese populations reflects their ethnic origin and linguistic affiliations to a great extent. This study characterizes β-globin gene cluster haplotypes in southwest Chinese minorities for the first time, and reveals the genetic variability and affinity of these populations using β-globin cluster haplotype frequencies. The results suggest that ethnic origin plays an important role in shaping variations of the β-globin gene cluster in the southwestern ethnic populations of China.

Figure 1. The location of the polymorphic restriction enzyme sites in the β-globin gene cluster.

Figure 2

Unrooted Neighbor-joining tree showing genetic and linguistic affinities among the studied populations and other Chinese populations (a), and the genetic relationship among Asian, American, European and African based on 5′ haplotype frequencies of the beta-globin gene cluster (b).

Figure 3. Outline map of Greater China indicating the geographic locations of Chinese ethnic populations sampled in present and previous studies.

Details of the populations are presented in Table 6. The map was created using Canvas Software version 11, ACD Systems of America, Inc. Seattle, WA, USA. www.acdsystems.com.