Association Analysis Of Polymorphism Of Breeding-related Candidate Genes And Litter Size In Sheep

Litter size is an important economic trait for sheep,which directly affects the economic efficiency of sheep farming.In this study,16 loci of nine genes,ESR1,LHCGR,LIFR,SMPD1,SMPD4,FLI-1,ACSS3,SDSL and GUCY1A1,were typed and associated with lambing number using Sequenom Mass ARRAY? SNP technique,and linkage disequilibrium analysis was performed for genetic loci with linkage.The main results are as follows:(1)The ESR1 gene rs399356740 locus produced significantly higher numbers of lambs in TA individuals than in TT individuals in the F1 population(P<0.05).(2)The LHCGR gene rs422326439 locus produced significantly higher numbers of lambs in AA individuals than in AC and CC individuals in the H1 population(P<0.05).The number of lambs produced by AG and AA haplotypes in rs422326439 and rs421442316 loci was extremely significant higher than that of CA haplotypes(P<0.01),and the number of lambs produced by AAAA haplotypes was significantly higher than that of CCAA,CAGA,CAAA and AAGA haplotypes(P<0.05).The rs407034399 locus was significantly higher than GT and TT lambing in all individuals for the GG type(P<0.05).None of the rs417651115 loci were significant for lambing numbers in this sheep population(P>0.05).(3)The LIFR gene rs412822164 locus produced significantly more lambs in individuals of TT type than CT and CC type in the TH population(P<0.05).None of the rs426207783 loci were significant for lambing numbers in this sheep population(P>0.05).(4)The SMPD1 gene rs402810592 locus was extremely significant in the F2 population with higher lambing numbers in the CC type than in the TC and TT types(P<0.01).None of the SMPD4 gene rs406673410 loci were significant for lambing number in this sheep population(P>0.05).(5)The rs420710013 locus of the FLI-1 gene had a extremely significantly higher number of lambs in the F1 population for the TT type than for the CC type(P<0.01)and a significantly higher number of lambs for the TT type than for the TC type(P<0.05).None of the rs597411006 loci were significant for lambing numbers in this sheep population(P>0.05).(6)The ACSS3 gene rs413161195 locus produced significantly more lambs in the H1 population in the GG type than in the AA type(P<0.05).The rs159826406 locus had a significantly higher number of lambs produced by type AA than type GG in all individuals(P<0.05).None of the rs419433409 loci were significant for lambing numbers in this sheep population(P>0.05).(7)The SDSL gene rs398864505 locus produced significantly more lambs in the TH population for the CC type than for the CT type(P<0.05).(8)The GUCY1A1 gene rs1089837400 locus produced a extremely significantly higher number of lambs in the TH population for the TT type than for the AA and TA types(P<0.01).In summary,a total of 11 loci significantly associated with lambingnumber traits were screened in five sheep populations in this study,which can be used as molecular genetic marker loci for breeding new high-quality meat sheep breeds(lines)in Ningxia region.