Abstract：Leptin receptor(LEPR) plays a pivotal role in regulating leptin function as leptin binding protein. Variation in the LERP gene has been associated with obesity in human and fat deposition in cattle, swine and other animals. In this study, three pairs of primers were designed respectively referring to bovine(Bos tauras) LERP exon 4, exon 5 and exon 8 as well as their contiguous parts sequence in GenBank, so as to investigate the variations in corresponding part of LERP gene in Tianzhu white yak, Gannan yak and Qinghai yak(Bos grunniens) by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis. The polymorphisms were observed at LERP exon 4 and exon 8 as well as their contiguous parts in yak. Two allelic variations containing five single nucleotide polymorphisms(SNPs) were observed including two missense mutations at LERP exon 4 and contiguous parts in three yak populations. Allele A was the most common allele and the polymorphism was low with PIC less than 0.25 at this region of LEPR gene in yak. Five SNPs including three missenses mutations were checked at LERP exon 8 and contiguous parts in yak, but alleles distributed disproportionably among three yak populations, such as alleles A→F observed in Tianzhu white yak, but alleles A→C in Gannan yak and Qinghai yak. Allele A was the most common allele, and that allelic and genotype frequency were significantly deviated from Hardy-Weinberg balanced (P<0.05). The polymorphism was higher or moderate with PIC more than 0.25 at LERP exon 8 in three yak populations. No polymorphism was found at LERP exon 5 and contiguous parts, but three SNPs were observed at intron 4 and intron 5 relative to bovine LERP gene sequence. Exon 8 for LEPR gene codes the amino acids consisting of C2 domain of LEPR where amino acids recognizes and binds ligand, for LEPR gene with much polymorphism, exon 8 would become a potential locus for genetic markers, in which it may be possible for traits regulation.
