Polymorphism Of UCP1 Gene And Its Association Analysis With Growth Traits In Sheep

To screen out the different loci of UCP1 gene affecting the growth and development of Ningxia high-quality mutton sheep,three-parent populations of Dorper,Small-tailed Han sheep,Tan sheep and their offsprings in the breeding of new breeds of Ningxia high-quality mutton sheep were selected in the present research.The different loci of the UCP1 gene in the three-parent populations were detected by targeted sequencing,and the bioinformatics analysis of missense mutation in the exon loci was carried out.The genotypes of different loci in progeny were detected by MassArray genotyping technique,and the relationship between different genotypes and growth traits was analyzed;and here are the main findings:1.There was a significant difference in 15 loci and an extremely significant difference in 25 loci among Dorper sheep,Tan sheep and Small-tailed Han sheep as screened breeds;after sequencing the UCP1 genes of 91 sheep from 3 sheep breeds by targeted sequencing technique.2.In this study,ten loci with a significant difference and five polymorphic loci of 384 hybrid offsprings of three breeds were selected for Massarray genotyping,and association analysis was conducted with phenotypic data of three stages.The results showed that the body length of GA type individuals at 18692021 locus was significantly higher than those of GG type individuals at 3 months old and 6 months old(P<0.05);the body weight of TT type individuals at 18693226 locus was significantly higher than those of CC and CT type individuals at 3 months old(P<0.05);the chest girth of 3 months old of TT type was significantly higher than those of CT type(P<0.05);the body weight and body length of 18692054 locus of-.ACCACCT individuals at 6 months old were significantly higher than those-.-individuals(P<0.05);the birth chest girth of GA type individuals at 18698197 locus was significantly higher than those of AA type individuals(P<0.05);the body length at 3 months old of GG type individuals was significantly higher than those of GA type individuals(P<0.05);the birth body length and birth chest girth of GA type individuals at 18698214 locus was significantly higher than those of AA type individuals(P<0.05);the birth height,birth length and six-month body weight of AG and GG type individuals at 18698315 locus was significantly higher than those of AA type individuals(P<0.05),the chest girth of GG type individuals at 6 months old was significantly higher than those of AA type individuals(P<0.05).The phenotype of the mutant was greater than that of the wild type.The chest girth at 18698264 locus of GG individuals was significantly higher than that of GT and TT individuals(P<0.05);the wild type was larger than the mutant.3.The linkage disequilibrium analysis was carried out on the loci with significant differences and polymorphisms among the above populations in the hybrid offsprings of three breeds and the following results were found:There were 4 haplotypes and 5 diplotypes at 18691776 locus and 18692033 locus of UCP1 gene in hybrids of the offsprings,that deviated from the theoretical values,which may be due to long-term artificial breeding,low sample size or other factors.Among five diplotypes,H4H4(GGCC)type was the dominant diplotype,and association analysis showed that the body height of the H3H4 type was significantly higher than that of the H2H3 type at 3 months old(P<0.05).There were 4 haplotypes in hybrid progeny at 18692223 and 18693167 loci,and H4(GC)was the dominant haplotype.Among 3 diplotypes,4H4(GGGG)had the highest frequency and was the dominant diplotype,and the association analysis showed that there was no difference among individuals of each diplotype.There were 4 haplotypes at 18698197 and 18698214 loci in hybrid progenies,where H4(GC)was the dominant haplotype.Among 6 diplotypes,H4H1(GAGA)had the highest frequency and was the dominant diplotype.The results showed that the birth chest girth of H4H2 was significantly higher than that of H2H2(P<0.05).The chest girth and body length of H4H4 individuals at 3 months old were significantly higher than those of H2H2 and H4H3 individuals;and the body length of H4H4 individuals at 3 months old was significantly higher than that of H4H1 individuals(P<0.05).The body height of H4H4 individuals was significantly higher than that of H4H2 individuals at 6 months old(P<0.05).To sum up,the UCP1 gene is polymorphic among three different breeds of Dorper sheep,Tan sheep and Small-tailed Han sheep,so it can be used as a selective gene for the growth,development and meat production performance of mutton sheep.In this experiment,18692021,18692054,18693226,19981997,18698214,18698214,18698315 loci and diplotype H3H4 consists of 18691776 and 18692033 loci,diplotype H4H4 and H4H2 consist of 18698197 and 18698214 loci have certain reference value in the breeding and can be considered as molecular markers of UCP1 gene for further research in the future.However,further research is needed to evaluate whether there will be an effect on the growth and development;and fat deposition characteristics of hybrid offsprings.