Relation of IGF-1 gene with concentrations of insulin-like growth factor-I, insulin and glucose blood serum in Khuzestan crossbreed cow

Selection via genetic marker increases annual genetic progress. One of these markers is IGF-I gene which plays an important role in growth, milk production, and reproductive activities. IGF-I gene of cow is located in chromosome 5. The aim of this study was to evaluate the polymorphism of exon 1 of IGF-I gene and its relation with insulin and blood serum glucose concentrations in Khuzestan crossbreed cow. To study the polymorphism of IGF-I gene, the jugular vein of 3 to 4 years old 93 crossbreed cows were blood sampled. DNA was extracted and polymerase chain reaction was performed to amplify a 249 base pair segment of exon 1 of the gene. SnaBI restriction enzyme was used for enzymatic digestion. Results showed that the frequency of genotypes AA, AB, and BB were 0.06, 0.53, and 0.41, respectively. AB genotype had the highest and AA genotype had the lowest frequency in the herd. The frequency of A and B alleles in this population were estimated 0.33 and 0.67, respectively. Observed heterozygosity of IGF-I gene in crossbreed cows was 0.526 while expected heterozygosity was 0.441. Serum IGF-I and insulin concentrations were significantly higher in BB genotype than AB and AA genotypes (P