Identifying genes associated with quantitative traits in pigs: Integrating quantitative and molecular approaches for meat quality

Abstract

Two major strategies are used to identify genes that are involved in complex traits, genome scanning and candidate gene approaches. While a quantitative trait locus (QTL) strategy relies on a scan of the entire genome combined with phenotypic measurements, a candidate gene approach tries to identify genes based on their possible role in the physiology of the traits. Both strategies are based on the integration between quantitative and molecular approaches. Over the last decade, enormous effort has been applied to identify and localize QTL involved in most of the economically important traits in pigs and a number of candidate genes were suggested and further validated according to a concordant position to the detected QTL and related functions. However, lacking of information in regards to identified genes within the identified QTL, and false-positive QTL are major constraints that limit the successful of this approach. Additional approaches, including a gene expression analysis of the divergence of phenotype of interest was integrated into a candidate gene analysis, in which a putative candidate gene is the one that could be statistically detected from the genes controlling large components of inheritable gene expression variation. Furthermore, a remarkable progress of molecular approaches by newly developed technique, a study of an interaction between genes and a holistic study of biological regulation, system biology, is underway. These continuations will assist the researchers to identify direct candidate gene for quantitative traits in animal breeding.