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

The genetic diversity and relationships among ethnic minority populations of southwest China were investigated using seven polymorphic restriction enzyme sites in the beta-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 beta-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 beta-globin cluster diversity in the Chinese populations reflects their ethnic origin and linguistic affiliations to a great extent. This study characterizes beta-globin gene cluster haplotypes in southwest Chinese minorities for the first time, and reveals the genetic variability and affinity of these populations using beta-globin cluster haplotype frequencies. The results suggest that ethnic origin plays an important role in shaping variations of the beta-globin gene cluster in the southwestern ethnic populations of China.