Estrogen receptor alpha (ER- alpha ) gene and bovine performance: is there any relation?

The objective of the study was to investigate ER- alpha gene polymorphism (A/G transition) in 5' region in consensus promoter for exon C, determine its allelic and genotypic frequencies and assess its association with cattle performance. Genomic DNA was extracted from 200 dairy Holstein cows in four farms in Isfahan province of Iran and the individuals were genotyped by PCR-RFLP technique. The DNA fragments were PCR-amplified and then digested with BglI endonuclease. Restriction fragments with 245 bp represented allele A and those with 168 bp and 77 bp indicated allele G. Allelic frequencies were 0.0742 and 0.9257, respectively for allele A and G, and the total distribution of AA, AG and GG genotypes was 0.010, 0.129 and 0.861, respectively. The population was in Hardy-Weinberg equilibrium. Using SAS software (Proc GLM), the effect of ER alpha gene polymorphism on cows' reproduction traits and calves' birth weight was investigated, but no significant relation was found. So it could be concluded that this SNP has no effect on traits under study and also is not in a linkage disequilibrium with other mutations affecting the reproduction traits or birth weight of cattle.