Studies On SNPs Of DGAT1 Gene And Its Association With Partial Economic Traits In Pigs

DGAT1 gene was selected in this experiment as a candidate gene for pig carcass and meat quality traits to study on the A3122G,C7545T,C7604T and 3'-UTR loci of this gene in five native breeds(NingXiang pig,TaoYuan black pig,DaWeizi pig,ShaZiLing pig,WuZiShan pig) and three foreign breeds(Duroc,Yorkshire,Landrace pig),and its associations between A3122G,C7545T and 3'-UTR loci of pig DGAT1 gene and carcass and meat quality traits of foreign breeds(Duroc,Yorkshire,Landrace pig) were reported in this paper.Rresults were obtained as follows:1.With the bioinformatics methods and public database resource,78 candidate mutation loci of pig DGAT1 gene were found,three of them were validated,which were A3122G,C7545T and C7604T.2.In this study,a TaqⅠenzyme digestion position was created in primer by using dCAPS software.The genetic variances of DGAT1 gene C7604T locus were detected with PCR-RFLP-TaqⅠ,the results showed that in this locus there were existed allele C,allele T,CC genotype,CT genotype and TT genotype.The freqrency of allele C and the CT genotype were dominant in all breeds,the highest freqrency of allele C was founded in ShaZiLing pig(0.9605),the lowest freqrency of allele C was founded in WuZiShan pig(0.8462),there haven't TT genotype in NingXiang pig and DaWeizi pig.All breeds in this locus showed low polymorphism(PIC＜0.25)and had little genetic variations.This SNPs were converted into dCAPS marker in this paper.3.The genetic variations of DGAT1 gene A3122G were detected with PCR-RFLP-AvaⅡ(Eco47Ⅰ),the results showed that in this locus there were existed allele A,allele G,AAgenotype,AG genotype and GG genotype.In local breeds the GG genotype and the freqrency of allele G were dominant while the AA genotype and the freqrency of allele A were dominant in exotic breeds.The backfat thickness of AA genotype in Yorkshire was significant difference lower than GG genotype,the effect was 19.18%(p＜0.05),in Duroc and Landrace AA genotype was lower than GG genotype while there were no significant difference.The lean percentage of AA genotype of Duroc and Landrace were significant difference higher than GG genotype(p＜0.05),theirs effects were 4.66%and 3.28% respectively.The fatness percentage of AA genotype in Duroc and Landrace was significant difference lower than AA and GG genotype,theirs effects were 29.55%and 26.77% respectively(p＜0.05).The marbling grade of AA genotype in Duroc was significant difference lower than AA and GG genotype(p＜0.05).The reserve losing of AA genotype in Large White was significant difference lower than GG genotype,the effect was 32.55% (p＜0.05).In shortly,Duroc,Yorkshire and Landrace were both showed that AA＜AG＜GG in backfat thickness,fatness percentage,marbling grade and reserve losing.Allele A had the positive effects on carcass and meat quality traits in pigs,we could improve lean percentage and reduce backfat thickness,fatness percentage by enhancing the freqrency of allele A. 4.The genetic variances of DGAT1 gene C7545T were detected with PCR-RFLP-HpaⅡ,the results showed that in this locus there were existed allele C,allele T,CC genotype,CT genotype and TT genotype.In local breeds the freqrency of allele T were dominant while the freqrency of allele C in exotic breeds.The backfat thickness of CC genotype in Duroc and Yorkshire were significant difference lower than TT genotype,theirs effects were 12.75%and 10.93%respectively(p＜0.05),in Landrace CC genotype was lower than TT genotype while there were no significant difference.The lean percentage of CC genotype in Yorkshire and Landrace were higher than TT genotype(p＜0.05),theirs effects were 4.91%and 2.37%respectively(p＜0.05).The fatness percentage of CC genotype in Duroc and Landrace were significant difference lower than TT genotype,theirs effects were 30.13%and 23.88%respectively(p＜0.05).The marbling grade of CC genotype in Duroc,Yorkshire and Landrace were significant difference lower than TT genotype (p＜0.05).In all,Duroc,Yorkshire and Landrace were both showed that CC genotype had lowest backfat thickness,fatness percentage and hightest lean percentage.Allele C had the positive effects on carcass and meat quality traits in pigs.5.The genetic polymorphisms of DGAT1 gene 3'-UTR in pigs were analyzed by using PCR-SSCP method.One SNPs,an G→A polymorphism was founded in DGAT1 gene 3'-UTR which was located in 7744bp of this gene.The G→A mutation created a Eco47Ⅲenzyme digestion position polymorphism.There was no significant difference between local breeds and foreign breeds in genetic diversity.The lean percentage of AGgenotype in Duroc was higher than AA genotype,the effect was 2.76%(p＜0.05),while The lean percentage of AG genotype in Yorkshire was higher than GG genotype,the effect was 4.37%(p＜0.05).The backfat thickness of AG genotype in Duroc and Landrace were significant difference lower than AA and GG genotype,in Duroc theirs effects were 14.39% and 13.95%respectively(p＜0.05),in Landrace theirs effects were 20.90%and 16.47% respectively(p＜0.05),in Yorkshire AG genotype was lower than AA and GG genotype while there were no significant difference.The fatness percentage of AG genotype in Yorkshire and Landrace were significant difference lower than GG genotype,theirs effects were 18.67%and 17.55%respectively(p＜0.05).The marbling grade of AG genotype in Yorkshire and Landrace were significant difference lower than AA and GG genotype (p＜0.05) AG genotype had the positive effects on growth,carcass traits and meat quality traits in pigs.This studies indicated that DGAT1 gene could be used as a candidate gene or molecular marker on the badkfat thickness,fatness percentage,lean percentage and other economic traits.6.The nucleotide sequence data reported in this paper have been submittened to GenBank and have been assigned the accession numbers:EU251427-28,EU258764～65,EU152052～55,EU151425～26,EU294420～30,EU374633～32.