Polymorphism Analysis and Expression Profile of the Estrogen Receptor 2 Gene in Leizhou Black Duck

Abstract

BackgroundOur previous study on the ovarian transcriptomic analysis in Leizhou black duck revealed that the ESR2 gene was involved in hormone regulation in reproduction and the estrogen signaling pathway related to reproductive performance was enriched. This suggested that ESR2 may have a functional role in the reproductive performance of the Leizhou black duck. Thus, this study aimed at evaluating the polymorphism of the ESR2 gene and its association with egg-laying traits and the distribution pattern of ESR2 mRNA in laying and non-laying Leizhou black ducks. MethodIn this study, genomic DNA was extracted from blood samples of 101 Leizhou black ducks to identify single nucleotide polymorphisms (SNPs) of the ESR2 gene to elucidate molecular markers highly associated with egg-laying traits. Four (4) each of laying and non-laying Leizhou black ducks were selected to collect different tissues to analyze the ESR2 gene expression. ResultsA total of 23 SNPs were identified and association analysis of the single SNP sites showed that SNPs g.56805646 T>C and exon 3-20G>A were significantly (P < 0.05) associated with egg weight. Ducks with CT and AG genotypes had significantly higher (P < 0.05) egg weights than their respective other genotypes. Haplotype association analysis of g.56805646 T>C and exon 320G>A showed that the haplotypes were significantly associated with egg weight where higher egg weight was seen in individuals with H3H4 haplotypes. In the hypothalamus-pituitary-gonadal (HPG) axis, the results of qRT/PCR showed that ESR2 mRNA was significantly (P < 0.05) expressed in the ovaries of both duck groups than in the hypothalamus and pituitary. In the oviduct, ESR2 was significantly (P < 0.05) higher in the infundibulum and magnum of laying and nonlaying ducks respectively. ConclusionThis study provides molecular marker for selecting Leizhou black ducks for egg production and provides theoretical knowledge for the study of the related biological functions of the ESR2 gene at the cellular level.

Research Note: Polymorphisms of gonadotrophin-releasing hormone gene and their association with growth traits in quail (Coturnix Coturnix)

“…Research on the identification of poultry genes and their association with economic traits is increasing, which has contributed to identifying new genetic markers to more accurately select animals to improve poultry growth performance ( Bhattacharya et al, 2019 ; Asiamah et al, 2022 ). Gao et al (2020) reported that 46 SNPs were detected in the GnRH gene of 2 Sichuan White goose populations.…”