New Evidences of Effect of Melanocortin-4 Receptor and Insulin-like Growth Factor 2 Genes on Fat Deposition and Carcass Traits in Different Pig Populations

J. L. Li,C. Y. Deng,F. E. Li,B. Zuo,Y. Z. Xiong,S. W. Jiang,M. G. Lei,R. Zheng,J. F. Chen

doi:10.5713/ajas.2005.1542

Abstract

The Melanocortin-4 Receptor (MC4R) and Insulin-like Growth Factor 2 (IGF2) are two important candidate genes related to fat deposition and carcass traits. MC4R was found on study on human obesity and then was studied as candidate gene affecting food intake and fat deposition traits in mice and pigs. Insulin-like Growth Factor 2 (IGF2) gene plays an important role on tumor cell proliferation and muscle growth. It also affects fat traits and live weight in pigs. In this paper, MC4R and IGF2 were studied as two candidate genes associated with important economic traits such as fat deposition and carcass traits in five different pig populations. Taq I-PCR-RFLP and Bcn I-PCR-RFLP were respectively used to detect the polymorphism of genotypes of MC4R and IGF2 genes. Different MC4R genotype frequencies were observed in four populations. IGF2 genotype frequencies were also different in two populations. The results of association analysis show both MC4R and IGF2 genes were significantly associated with fat deposition and carcass traits in about 300 pigs. This work will add new evidence of MC4R and IGF2 affecting fat deposition and carcass traits in pigs and show that two genes can be used as important candidate genes for marker assistant selection (MAS) of growth and lean meat percentage in pigs.

Highlights

New Evidences of Effect of Melanocortin-4 Receptor and Insulin-like Growth Factor 2 Genes on Fat Deposition and Carcass Traits in Different Pig Populations
Insulin-like Growth Factor 2 (IGF2) genotypes marked with CC (451 bp), CD (451 bp+84 bp+367 bp) and DD (84 bp+367 bp) (See Figure 2)
Genotype frequency of IGF2 was not showed due to there is no polymorphism on this locus which was reported by Liu et al (2003) in all populations

Summary

INTRODUCTION

Regulating cell proliferation and apoptosis (Jones and Clemmons, 1995; Yu and Rohan, 2000; Kim et al, 2005). As a part of the central melanocortin system (CMS) which Chromosome 2 in pigs (SSC2) (Jeon et al, 1999; Nezer et regulates food intake and metabolize, MC4R regulates the al., 1999) It plays an important role on tumor cell feeding behavior and body weight cooperated with Leptein proliferation, muscle growth and genomic imprinting. The insulin-like growth factors (IGFs) and their receptors as well as their binding proteins play key roles in intron and the structure of protein have been found to affect on fat and carcass traits significantly (Liu et al, 2003) Based on these two variances G→C, we designed two pairs of primers and used Bcn I-PCR-RFLP to analyze the association of the variances with fat and carcass traits in a total of 311 pigs belonging to different populations. Important evidences that MC4R, IGF2 are two important candidate genes to be used for selecting of fat deposition and lean meat percentage in pig industry

MATERIALS AND METHODS

RESULTS

Allele frequency

Population C Population D Population E

This work was supported by the grants from National