Genetic polymorphism in the POU1F1 gene in Kalahari Red and two Nigerian goat breeds and their relationship with litter size

POU1F1 gene controls cell differentiation and animal growth by binding to target DNA promoter sequence, thereby auto-regulating its own expression and expression of growth hormone (GH), prolactin (PRL) and thyroid-stimulating hormone beta sub-unit (TSHβ) genes. Therefore, the exploration of caprine POU1F1 gene polymorphisms may be vital in the formulation of conservation and breed improvement strategies.  In this study, POU1F1 gene was characterized for sequence polymorphisms in 366 individuals from two Nigerian goat breeds ((West African Dwarf (WAD) and Red Sokoto (RS)) and one South African goat breed (Kalahari (KR)). The effects of polymorphisms on litter size were investigated using linear mixed model. Two intronic mutations (g.306G>A and g.11236C>T) were identified. However, no significant association was found between the Single Nucleotide Polymorphisms (SNPs) and litter size in the three populations. The genetic distance based on POU1F1 investigated region revealed that the two Nigerian breeds and the South African breed were identical (pairwise genetic distance of 0.00). Phylogenetic tree constructed from the pairwise distance clustered the three breeds into a single clade with the two Nigerian goat breeds having a more recent common ancestor. Structural analysis of the POU1F1 protein confirmed that Pit-Oct-Unc transcription factors domain (POU) and Homeodomain (HOX) domains are conserved in mammals, with several overlapping sub-domains across the same region in all the three populations. We found a subdomain Subfamily of SANT domain or myb/SANT-like domain in Adf-1 (MADF) in goat, cattle, buffalo and camel that has not been reported in mammals