FUT2 polymorphism in Latin American populations.

BACKGROUND

The secretor type α(1,2)fucosyltransferase gene (FUT2) is known to be rich in population-specific polymorphisms. However, genetic variations of FUT2 have not been well examined in Latin American populations in which nonsecretors are rare.

METHODS

Conventional polymerase chain reactions and direct sequencing were performed to detect single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) of FUT2 in Mexicans including Americans of Mexican ancestry, Puerto Ricans, Caribbeans, and Colombians. FUT2 alleles were determined by cloning into plasmids or PHASE software. The impact of uncharacterized missense SNPs on the enzyme activity were examined by transient transfection assays and estimated by several software programs.

RESULTS

Three alleles, Se, Se, and se, were common, and the frequency of nonsecretors was relatively low in the studied populations. We also encountered several alleles specific to Africans, Europeans, and South and East Asians including a South Asian-specific se. In contrast to the in silico prediction, a transient expression study suggested that both of two missense SNPs, 235G > A and 304G > A, did not impair the enzyme activity.

CONCLUSIONS

The allelic polymorphism of FUT2 suggests that the modern Latin American populations were formed via genetic admixture among Native Americans and populations whose ancestors migrated from other continents. In this study, we have observed a discrepancy between in silico and functional analyses for FUT2 for the first time. Therefore, experimental functional analysis is required for evaluation of SNPs of FUT2.