Single-minded 1 Gene Mapping and Its Variants Association with Growth, Carcass Composition and Meat Quality Traits in the Pig

X F Zhao,N Y Xu,Z Chen,X L Guo,Q Wang

doi:10.5713/ajas.2008.70056

Abstract

: Single-minded 1 gene (SIM1) is a homolog of Drosophila SIMI gene which plays a key role in the midline cell lineage of the central nervous system and is implicated in the regulation of feeding behavior and obesity in the human and mouse. In this study, porcine SIM1 gene was firstly mapped to chromosome 1p13 using radiation hybrid (RH) mapping and two polymorphisms were detected at position 607 (A/G) in SIM] intron7 and position 780 (C/T) in SIM1 exon8. The last substitution was genotyped in a 364 F2 animal-population and an association analysis of these genotypes was performed with growth, carcass and meat quality traits by the statistical animal model. The results showed the significant influence of the SIM1 genotype on growth (p<0.05): live weight at birth, later period of growth and average daily gain; and effects on carcass composition (p<0.05): weight of head and buck kneed foreleg, backfat depth, loin eye area, carcass leaf fat and ham fat weights; and traits related to intramuscular fat content (p<0.05).

Highlights

Single-minded 1 (SIM1) gene has been identified as a homolog of Drosophila SIM gene, which plays a key role in the midline cell lineage of the central nervous system (Crews et al, 1988)
This is the first time the location of SIM1 on the chromosome has been confirmed by radiation hybrid (RH) mapping and for the association with the polymorphism to be analyzed based on a standard animal model with growth, carcass composition and meat traits in the pig
Patients with chromosome abnormalities involving the region where the SIM1 gene is located present with some Prader-Willi syndrome-like clinical and behavioral features such as hyperphagia, severe obesity, abnormal head circumference and small hands and feet (Varela et al, 2006), which suggested early-onset obesity and hyperphagia were determined by the SIM1 gene

Summary

Introduction

Single-minded 1 (SIM1) gene has been identified as a homolog of Drosophila SIM gene, which plays a key role in the midline cell lineage of the central nervous system (Crews et al, 1988). SIM proteins belong to a family of transcription factor called bHLH/PAS (basic helix-loop-helix/PeriodArnt-Sim). SIM1 is expressed in the developing kidney and central nervous system, and is essential for the formation of the supraoptic and paraventricular (PVN) nuclei of the hypothalamus. Loss-of-function experiments in mice showed that the bHLH/PAS transcription factor SIM1 is essential for the differentiation of PVN neurons (Michaud et al, 1998); in the absence of SIM1 almost all PVN neurons failed to develop and homozygous SIM1-deficient mice died shortly after birth, but heterozygous SIM1-deficient mice survived and

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