5' and 3' β-globin haplotypes in purepechas and Tarahumaras, two Mexican indigenous groups

The purpose of this study was to determine the β-globin cluster haplotype variability of two Mexican indigenous groups-Purepechas (PUR) and Tarahumaras (TAR)-and their relationship with other world populations.

The 5' and 3' haplotypes (Hp) of the β globin cluster in 71 PUR and 53 TAR individuals were analyzed. Five polymorphisms in the 5'Hp (ε, (G) γ, (A) γ, 5'ψβ and 3'ψβ) and five in the 3'Hp (IVS2: 16, 46, 74, 81 and 3' end +339) were identified by restriction enzymes and direct DNA sequencing. 5'Hp and 3'Hp frequencies in PUR and TAR were compared with reported frequencies from 47 and 10 worldwide populations, respectively.

Sixteen different 5'Hps were observed in the indigenous Mexican groups, 11 in each population, with the most common being 5'Hp 1. Eight 3'Hps were detected, seven in PUR and six in TAR, the most frequent being 3'Hp C. Three new 3'Hps were found, A8 (CTGCT) in both populations, C9 (GTGCA) in TAR and E1 (GTTCT) in PUR. The comparative analysis showed that 5'Hp frequencies in PUR were significantly different than those in all populations except the Brazilian-Guarani, while TAR were significantly similar to Aché and North Han Chinese. 3'Hp frequencies were similar between PUR and TAR, as well as with Nuu-Chah-Nulth, Mongolian and Sumatran populations.

The 5'Hp analysis showed great variability in worldwide populations, including PUR and TAR, while 3'Hp frequencies were similar among indigenous Mexican and other populations with Asiatic origins. This suggests that 5'Hp exposes the microevolutionary process of each population and the 3'Hp establishes genetic relationships among populations.