Polymorphism study in STAT1 gene at two positions in Holstein cows of Isfahan province

This experiment was performed to study a mutation in STAT1 gene and calculate allelic and genotypic frequencies. The STAT1 gene is one of a series of the genes which passes biological signals from out of nucleus into the inner parts. This factor has a regulator action in the gene expression and function. STAT1 is located on chromosome-2 at 2q32.2 containing 20 introns and 19 exons. Three hundred fifty blood samples were collected from Holstein cattle herds and DNA was extracted using modified salting out method. Two positions were studied. One fragment with 321bp polymerase chain reaction (PCR) products was studied but polymorphism was not observed. Another fragment with 314bp by specific primer pairs was studied and PCR products were electrophorsed. RFLP method was used to for genotyping and the resultant PCR products were digested by Pag1 enzyme. Genotyping results showed that the genotypes BB, CC, DD, AC, AB, BC, BD, CD with frequencies of 0.0999, 0.0856, 0.0285, 0.0514, 0.0085, 0.0341, 0.0085 and 0.427; and the alleles A, B, C, D with frequencies 0.0298, 0.125, 0.342, 0.5032. Results showed that in STAT1 gene there is not Hardy-Weinberg equilibrium in this population.