Variations in Interleukin-10 Gene Underlying Trypanotolerance in Nigerian Indigenous Cattle

Abstract

This study looked into trypanotolerance as one of the interesting physiological traits of indigenous Nigerian cattle (Muturu) which has been well adapted to the tsetse infested zone of the middle belt and southern parts of Nigeria. Interleukin-10 gene amplification, sequencing and bioinformatics methods were applied to the genetic data of the Nigerian Muturu cattle to detect the genetic divergence that may be associated with trypanotolerance in the Muturu cattle as compared to the White Fulani cattle. Trypanosomosis in livestock and man is characterized by cellular changes and damages resulting in great loss in production and sometimes death. IL-10 has been implicated as a candidate gene in trypanotolerance in N’Dama. Thus, to uncover Muturu genetic signatures underlying trypanotolerance, this study compared variations in IL-10 gene of Muturu and White Fulani cattle. Variations in IL-10 gene (exon 1) were identified using DNA sequence polymorphism programme (DnaSP) version 5.10.01 to estimate haplotype frequencies, nucleotide diversity and sequence conservation. The results revealed twenty-four single nucleotide polymorphisms (SNPs) present in White Fulani while only one SNP was present in Muturu, showing that IL-10 gene was more conserved in the Muturu cattle. Eight haplotypes were present in exon 1 of IL-10 gene of White Fulani while that of Muturu was one. Three motifs were common to the two cattle breeds, while two others were found in White Fulani population alone. Prediction of secondary protein structure showed that the gene is a mixed folding protein in White Fulani while it is not in Muturu. The study concluded that the Muturu displayed clear genetic differences compared to White Fulani breed. SNPs (24) detected in White Fulani and one in Muturu could serve as useful marker for association studies with trypanotolerance while improvement of trypanotolerance in susceptible breeds can be achieved through gene manipulation using IL-10 gene.