Single Nucleotide Polymorphism Exploring the 5'-Regions of Estrogen Receptor-${\alpha}$ Gene and Association With Reproduction Performance and Milk Yield in Hanwoo and Holstein Dairy Cattle

Estrogen Receptor-${\alpha}$ 유전자 5' 영역의 Single Nucleotide Polymorphism의 탐색과 한우와 Holstein에서 번식능력 및 산유능력과의 관계

This study was conducted for SNPs in the 5'-regions of estrogen receptor-${\alpha}$ (ESR-${\alpha}$), and association with calving interval (CI), service per conception (SPC) and 305 days milk yield in Hanwoo and Holstein dairy cattle. The genetic improvement was incurred low reproduction performance. The objective of this study was to investigate connections between single nucleotide polymorphisms (SNP) of Estrogen receptor-${\alpha}$ (ESR-${\alpha}$) with reproduction performance (calving interval, service per conception, and 305 d milk yield) in Hanwoo and Holstein dairy cattle. Hanwoo and Holstein blood samples were collected from 183 and 124 dam of breeding farms and DNA was extracted. Primer design was based on NCBI GenBank (Accession No. AY340579). The PCR-RFLP method with Bgl I was used to genotype the cattle. The result showed two variants of the ESR-${\alpha}$ gene. The Bgl I cut the 492 bp amplification product into 322 bp and 170 bp fragments for allele G, while allele A remained uncut, resulting in two restriction fragments for homozygote G/G and three fragments for heterozygote A/G. We found two of different genotypes in these breeds, A/G and G/G. In Hanwoo, the A/G genotype frequency was 0.13, and G/G was 0.87. The CI of A/G was $382.18{\pm}10.03$ days, and G/G was $381.69{\pm}5.22$ days. The SPC of A/G was $1.62{\pm}0.16$, and G/G was $1.32{\pm}0.04$. While CI showed no significance difference, SPC exhibited significant difference (p<0.05). In Holstein cattle, the frequency of genotype A/G was 0.02 and G/G was 0.98. The 305 days milk yield of A/G was $7,253.00{\pm}936.00kg$ and of G/G was $8,747.51{\pm}204.88kg$, showing no significant difference.