Study On Genes Related To The Reproduction Trait Based On Whole Genome Resequencing In Prolific Suffolk Sheep

Objective: Prolific Suffolk sheep is a new breeding line with high-quality meat and prolific performance in Xinjiang China.This study aims to analyze the molecular mechanism of reproductive traits in Prolific Suffolk sheep.High-throughput sequencing technology was used to re-sequence the Prolific Suffolk sheep,Suffolk sheep and Hu sheep.Then screen for genes related to reproduction.The results of the study will help clarify the genetic basis of this species,and provide the basis for breeding the multiparous mutton sheep.Methods:(1)50 Prolific Suffolk sheep,20 Hu sheep and 20 Suffolk sheep were re-sequenced by using the whole genome resequencing technology(WGS),and the whole genome selection signals were used to analyze the specific reproduction-related genes in the species by population fixation index(FST)and heterozygosity analysis methods..(2)FST and heterozygosity were used to detect the differential genes related to reproduction in multi-lamb group and single-lamb group of Suffolk sheep.(3)The MTNR1 A derived from the differential genes was used as a candidate gene for reproductive traits in Hu sheep,Prolific Suffolk sheep and Chinese Merino sheep(Xinjiang military reclamation type).The polymorphisms and haplotypes of MTNR1 A gene were analyzed by gene cloning and relationships between SNPs and haplotypes of MTNR1 A gene and litter size were analyzed by least square method.Results:(1)5,245.855 G raw data and 5,236.338 G high-quality clean data of genome were obtained by WGS.Prolific Suffolk were screened reproduction-related genes including 14 WNT10 A,SENP2,WNT6,et al,.Prolific Suffolk were screened 23 specific genes including ARHGEF4,CATIP,CCDC115,et al,.(2)28 differential genes and 20,353,971 SNPs related to reproductive traitwere screened between multi-lamb group and single-lamb group,including ADAMTS5,CAB39 L and MTNR1 A genes,et al,.(3)SNP1(Chr26.15,099,314,G735A),SNP2(Chr 26.15,099,296,G753A)and SNP3(Chr 26.15,099,204,C845A)were detected in exon2 of MTNR1 A gene.There were three genotypes of each SNP site in Hu sheep,Prolific Suffolk sheep and Chinese Merino sheep(Xinjiang military reclamation type).The GG genotype of SNP1 and the GG genotype of SNP2 were significantly related to the litter size in Prolific Suffolk sheep(P<0.05),and the haplotype H1 was extremely significantly related to the litter size(P <0.01).The GG genotype of SNP1,GG genotype of SNP2,and CC genotype of SNP3 were significantly related to the litter size in Chinese Merino sheep(P<0.05).Conclusion:(1)23 specific genes and 87 SNPs were screened by WGS in Prolific Suffolk sheep.(2)28genes and 180 SNPs related to reproductive traits were screened in Prolific Suffolk sheep.(3)The SNP1 GG genotype,SNP2 GG genotype and haplotype H1 of MTNR1 A gene exon2 can be used as molecular markers of high reproduction trait for marker-assisted selection breeding programs in Prolific Suffolk sheep.The SNP1 GG genotype,SNP2 GG genotype and SNP3 CC genotype of MTNR1 A gene exon2 can be used as molecular markers of high reproduction trait for marker-assisted selection breeding programs in Chinese Merino.