Genotype frequencies of C/T-13910 and G/A-22018 polymorphisms in a Colombian Caribbean population do not correspond with lactase persistence prevalence reported in the region

Abstract

Introduction: The C/T_-13910 and G/A^-22018 polymorphisms located upstream of the lactase gene are reliable predictors of lactase persistence in Caucasian-derived populations. Assessing the presence and distribution of these polymorphisms in other populations is central to developing genotyping assays and understanding the evolutionary mechanism behind this trait in several human populations.
Objective: Genotyping the C/T_-13910 and G/A_-22018 polymorphisms in a sample of Colombian Caribbean individuals.
Materials and methods: The polymorphisms were identified through Polymerase Chain Reaction/Restriction Fragment Length Polymorphism. Amplified fragments were digested using Hinf I and Hha I. Arlequin v. 3.1 was used to determine allelic and genotypic frequencies, Hardy Weinberg equilibrium, and linkage disequilibrium.
Results: Genotypic frequencies were CC (81.4%), CT (18.6%), and TT (0%) for the C/T_-13910 polymorphism. Frequencies were AA (55.5%), GA (45.5%), and GG (0%) for the G/A_-22018 polymorphism. No linkage disequilibrium was found between the two loci. Only the locus containing the C/T_-13910 polymorphism was found in Hardy Weinberg equilibrium.
Conclusion: The allelic and genotypic distributions observed in this first genotyping study in a Colombian Caribbean population indicate a distribution pattern different from the one of the North European Caucasians and do not correspond to the lactase persistence prevalence reported for Caribbean populations.