Molecular Characterization,Expression Profile Of The FSHR Gene And Its Association With Egg Production Traits In Muscovy Duck

Muscovy duck is popular with more and more consumers because of its rich nutrition and it is regularly regarded as a good food for healthy.Muscovy duck is a meat-type breed with low egg laying performance and short laying period.Especially,its laying rate is significantly decreased at the late laying period.Therefore,to improve the Muscovy duck egg production performance,it is important to identify polymorphisms related to egg laying traits for molecular marker assisted selection.In the present study,the FSHR gene was selected as the candidate gene for the egg production.The full-length C DS of the Muscovy duck FSHR gene was cloned and its expression was analyzed in different tissues.Moreover,the polymorphisms was scanned and their association with egg production traits was investigated.In this study,the c DNA of Muscovy duck FSHR was amplified through RT-PCR and cloning.Consequently,three alternative splice variants,named FSHRTV1,FSHRTV2 and FSHRTV3,were obtained and their C DS length was 2202 bp,2184 bp,and 2082 bp,respectively.The protein sequence analysis found that the three alternative splice variants encoded 198,299 and 693 amino acids,respectively.FSHRTV1 and FSHRTV2 were generated by a 120 bp insertion at exon 7 and a 201 bp insertion at exon 9,respectively,both of which could result in the introduction of a premature stop codon.The expression analysis of the Muscovy duck FSHR gene showed that it was predominantly expressed in ovary(P = 0.0162)and then followed by lung,live r and abdominal fat.However,lower levels were found in other tissues including pituitary,brain,sebum,spleen,kidney,leg muscle,hypothalamus,cerebellum,heart,and breast muscle.A total of 223 white female Muscovy ducks from the same batch of commercial line(M103)were obtained from the Wens Foodstuff Company(Yunfu,Guangdong Province,C hina).Three egg productio n traits including age at first egg(AFE),egg production at 33 weeks of age(E33W),and egg production at 59 weeks of age(E59W)were observed and recorded for marker–trait association analysis.The polymorphism of the FSHR gene was identified by PCR and SNaPshot.A total of 16 SNPs including 4 at the coding region were found in the 2082-bp FSHR gene.Moreover,the SNP of C320 T was found to be significantly associated with egg production at 59 weeks(P < 0.05),and the CT genotype was advantageous for egg production at 59 weeks.The SNP of A227 G was in significantly association with the age at first egg(P < 0.05),and the AG genotype was advantageous for earlier egg production.In general,this study revealed the genomic structure,expression profile and different transcripts of the Muscovy duck FSHR gene,and two SNPs were found to be associated with egg production traits.These data indicated that the FSHR gene might play an important role in egg production performance of Muscovy duck,and this gene could be used as a molecular marker for the improvement of the Muscovy duck egg production.