SNP Discovery in the Leptin Promoter Gene and Association with Meat Quality and Carcass Traits in Korean Cattle

E R Chung,K H Shin,K Y Chung,S C Shin

doi:10.5713/ajas.2008.80112

Abstract

Leptin, the hormone product of the obese gene, is secreted predominately from white adipose tissue and regulates feed intake, energy metabolism and body composition. It has been considered a candidate gene for performance, carcass and meat quality traits in beef cattle. The objective of this study was to identify SNPs in the promoter region of the leptin gene and to evaluate the possible association of the SNP genotypes with carcass and meat quality traits in Korean cattle. We identified a total of 25 SNPs in the promoter region (1,208-3,049 bp upstream from the transcription start site) of the leptin gene, eleven (g.1508C>G, g.1540G>A, g.1545G>A, g.1551C>T, g.1746T>G, g.1798ins(G), g.1932del(T), g.1933del(T), g.1934del(T), g.1993C>T and g.2033C>T) of which have not been reported previously. Their sequences were deposited in GenBank database with accession number DQ202319. Genotyping of the SNPs located at positions g.2418C>G and g.2423G>A within the promoter region was performed by direct sequencing and PCR-SSCP method to investigate the effects of SNP genotypes on carcass and meat quality traits in Korean cattle. The SNP and SSCP genotypes from the two mutations of the leptin promoter were shown to be associated with the BF trait. The average BF value of animals with heterozygous SNP genotype was significantly greater than that of animals with the homozygous SNP genotypes for the g.2418C>G and g.2423G>A SNPs (p<0.05). Analysis of the combined genotype effect in both SNPs showed that animals with the AC SSCP genotype had higher BF value than animals with BB or AA SSCP genotypes (p<0.05). These results suggest that SNP of the leptin promoter region may be useful markers for selection of economic traits in Korean cattle.

Highlights

The challenge to the beef cattle industry in Korea is the production of cattle that exhibit satisfactory or superior meat quality
We identified a total of 25 polymorphic sites in leptin promoter region (Figure 1)
The leptin has been suggested as an excellent candidate gene for genetic variation in carcass and meat quality traits in beef cattle (Buchanan et al, 2002; Schenkel et al, 2005; Shin and Chung et al, 2007a)

Summary

Introduction

The challenge to the beef cattle industry in Korea is the production of cattle that exhibit satisfactory or superior meat quality. Marbling (intramuscular fat) is the most important meat quality trait in Korea because carcass value is primarily determined by the degree of marbling. Eating quality traits such as taste, juiciness and tenderness of meat, are influenced by the amount of intramuscular fat (Platter et al, 2005). The expression and secretion of leptin is highly correlated with body fat mass and adipocyte size (Houseknecht et al, 1998). It affects regulation of food intake, energy partition and body composition (Houseknecht et al, 1998; Baile et al, 2000; Dai et al, 2007).

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Conclusion