Distribution of Allele Frequencies at 5′-Flanking Region of CYP19 and ERα Genes between Iranian Simmental and Three Indigenous Cattle Breeds

This study was performed to investigate two polymorphic sites from Cyp19 gene (PvuII and MspI) and one polymorphic site from ER? gene (SnaBI) in four cattle breeds including Mazandarani, Taleshi, Sistani and Simmental. In overall 278 samples for CYP19 and 206 samples for ER? marker sites were genotyped using polymerase chain reaction single-strand conformation polymorphism (PCR-RFLP) procedure. For CYP19/PvuII, the frequency of A allele ranged from 0.89 in Mazandarani to 0.98 in Taleshi. For CYP19/MspI, Taleshi was the only monomorphic breed with just AA genotype. Other breeds were poly-morphic with A allele frequency ranging from 0.93 (Simmental) to 0.98 (Sistani). No BB individuals were observed in the studied sample. Considering two loci in combination with each other, only 5 out of 8 theo-retically possible combined genotypes were observed in the genotyped samples. For ER?/SnaBI, all popula-tions showed polymorphism. The highest and lowest frequencies of A allele were observed in Sistani (0.55) and Simmental (0.96), respectively. Based on Nei’s method, the most genetic distance was observed be-tween Sistani and Simmental and the least genetic distance was observed between Mazandarani and Taleshi breeds. The results of the present study showed significant differences in genotypic and allelic frequencies among four investigated breeds. These findings may be used in further researches, such as association stud-ies for performance traits in cattle breeding.