ABSTRACT
Variation in quantitative traits is due to the combination of genetic and non-genetic factors. Identifying such genetic factors by associating the trait variation with genotypic differences at certain loci is referred to as quantitative trait loci (QTL) mapping. In other words, the goal of QTL mapping is to identify regions of the chromosome that are associated with the phenotype of interest. More specifically, we would like to estimate the total number of QTL, their locations on the chromosomes, and the magnitude of their effects on the phenotypic value. It has been widely accepted that genetic markers can be used to study QTL (Sax 1923, Thoday 1960, Jayakar 1970), where such markers are identifiable and presumably closely linked to genes that affect the trait under investigation. QTL mapping holds the promise of locating genes underlying quantitative traits which help further investigate and manipulate the genes to improve the trait, and thus, it has attracted considerable attention in the research community recently.
