Polymorphisms Of A-FABP, H-FABP Genes And Their Association With Carcass And Meat Quality Traits In Yak

A-FABP and H-FABP as a member of the fatty acid binding protein (FABPs)family, play a pivotal role in regulating intracellular fat concentration and then affectintramuscular fat (IMF) in mammalian. So H-FABP and A-FABP was suggested as acandidate gene as it affects the beef quality. single nucleotide polymorphisms (SNPs)was investigated at A-FABP and H-FABP partial section in Gannan yak，Qinghai yak、Tianzhu white yak、wild yak and bovine by polymerase chain reaction-single strandconformational polymorphism (PCR-SSCP) so as to analyse their molecular geneticcharacteristics. The association between genetic polymorphisms with carcass andmeat quality traits were analyzed by using general linear model. To explore theprobability of H-FABP and A-FABP as candidate gene with carcass and meat qualitytraits of Gannan yak population. The main results were as follows:Five novel SSCP patterns, representing five different alleles A-E were identifiedin amplified region of Gannan yak、Qinghai yak and Tianzhu white yak A-FABP.With alignment of the bovine (Bos tauras) and yak A-FABP allelic sequences, sixSNPs including a synonymous mutation（c.4222A>G）at exon4were checked in yak.SNP c.*94T>A in3’-UTR of A-FABP which was only detected in yak populationrepresented one of genetic characteristics of yak that differ from the bovine. Allelesdistributed disproportionably among three yak populations, such as only alleles A-Cwere observed in Tianzhu white yak and alleles A-D in Qinghai yak. This may berelated to geographical distribution and breeding methods of different yak populations.Different genotypes of SNP locus was grouped,its relationship with carcass and meattraits of Gannan yak was analyzed using the general linear model. Carcass weight ofAA genotype were significantly different from that of AC genotype(P<0.01) in2.5～3years old gannan yak.The significant diference was found between the genotypes ofAA and BB for tenderness (P<0.01), as well as between the genotypes of AA and ABfor Carcass weight (P<0.05).There were no significantly difference between thedifferent genotypes with meats traits in other age. The mutations in amplified regionof yak A-FABP would become a potential locus for genetic markers of carcass andmeat quality traits of yakFive genotype and three different alleles A-C were identified in amplified regionof Gannan yak、Qinghai yak、Tianzhu white yak、wild yak and bovine H-FABP. Withalignment of the allelic A, two SNPs including c.17-2C>T in5’-UTR andc.17+120G>A in intron1were checked. Different genotypes of SNP locus wasgrouped,its relationship with carcass and meat quality traits of Gannan yak wasanalyzed using the general linear model Loin muscle area of BB genotype weresignificantly different from that of AA genotype(P<0.05) in3～3.5years old Gannanyak. The result showed that AB genotype of Carcass weight and Loin muscle areawere respectively significantly different from that of AA genotype(P<0.01andP<0.05),Carcass weight of BB genotype and BC genetype were respectivelysignificantly different from that of AB genotype(P<0.05and P<0.01),The significantdiference was found between the genotypes of AA and AB for Cooked meat percentage (P<0.05), as well as between the genotypes of BC and AA for Loin musclearea in4.5～5years old Gannan yak (P<0.01). The mutations in amplified region ofyak H-FABP would also become a potential locus for genetic markers of carcass andmeat quality traits of yakMutation site in CDS(coding domain sequence) of H-FABP gene in Gannan yakwas checked by PCR product pooling method so as to analysis the polymorphism andputative the characters of amino acid sequence by bioinformatics. The result showedthat sequence of CDS in Gannan yak H-FABP gene was same as Jiulong yak, but onesynonymous mutation（*76G>A）at exon3was detected in yak by sequence alignmentwith bovine.H-FABP proteins of Gannan yak may play biological function mainly inthe cytoplasm because obvious hydrophobic and transmembrane helical region andsignal pep-tide were not found in deduced amino acid sequence. The putativesecondary structure of H-FABP was mixed type primarily composed of α-helix andβ-extended in Gannan yak.