Polymorphism of Adipocyte Fatty Acid-binding Protein Gene(A-FABP) in Yak(Bos grunniens)

Adipocyte fatty acid-binding protein(A-FABP),as a member of the fatty acid binding protein(FABPs) family,play a pivotal role in regulating intracellular fat concentration and then affect intramuscular fat(IMF) in mammalian.So A-FABP was suggested as a candidate gene of IMF in some species of livestock and poultry.In this study,single nucleotide polymorphisms(SNPs) was investigated at A-FABP intron 3,exon4 and 3′-UTR in Gannan yak,Qinghai yak and Tianzhu white yak(Bos grunniens) by polymerase chain reaction-single strand conformational polymorphism(PCR-SSCP) so as to analyse their molecular genetic characteristics.Five novel SSCP patterns,representing five different alleles A-E were identified in three yak populations.With alignment of the bovine(Bos tauras) and yak A-FABP allelic sequences,six SNPs including a synonymous mutation(c.4222AG)at exon 4 were checked in yak.SNP c.*94TA in 3′-UTR of A-FABP which was only detected in yak population represented one of genetic characteristics of yak that differ from the bovine.Alleles distributed disproportionably among three yak populations,such as only alleles A-C were observed in Tianzhu white yak and alleles A-D in Qinghai yak.This may be related to geographical distribution and breeding methods of different yak populations.The mutations in amplified region of yak A-FABP would become a potential locus for genetic markers of meat quality traits of yak as it showed moderate polymorphism with PIC in the range of 0.29-0.36 and higher effective number of alleles(Ne).