Insulin-like Growth Factor 1 Gene Sequence Variations in Bapedi Sheep and Their Association with Morphometric Traits

Background: The study was conducted to identify the Insulin-like growth factor 1 (IGF1) gene polymorphism and its association with morphometric traits in Bapedi sheep breed in the Limpopo Province of South Africa. Methods: Blood samples were collected from hundred and twenty-seven (n = 127) South African Bapedi sheep aged between 1 to 5 years. The Deoxyribonucleic acid (DNA) was extracted, amplified, and sequenced for the IGF1 gene. DNA sequencing was used to identify the sequence variations of the IGF1 gene in South African Bapedi sheep. Result: The results showed that two nonsynonymous single nucleotide polymorphisms (SNPs) of the IGF1 gene in 5’ flanking region positions 855G greater than C and 857 greater than A were identified. Two genotypes (GG and GC) and (AA and AB) were discovered from each of the identified SNP. The results also indicated that the used population was not in the Hady-Weinberg Equilibrium. Marker trait association findings for SNPs 855G greater than C and 857 greater than A showed that there was statistical relationship between the genotypes with body weight, heart girth, withers height, sternum height, rump height and body length. Dominant genotype GG and AA had the highest impact on all the traits. IGF1 gene at 5’ flanking region of Bapedi sheep had SNPs (855G greater than C and 857 greater than A) at positions 855 and 857 bp with two genotypes each (GG and GC) and (AA and AB), respectively. Therefore, genotype GG of SNP 855G greater than C and genotype AA of SNP 857 greater than A of IGF1 gene might be used as a genetic marker when improving morphometric traits.