ABSTRACT
The location of a quantitative trait loci (QTL) can correspond to the segregation of one or several genetically linked genes. When the metabolic pathways linked to a trait are known, candidate genes can be chosen amongst structural or regulational genes involved in these pathways. When one or several candidate genes have been chosen, experiments must be carried out to select the most likely candidates. The molecular variation of a candidate gene can be studied in a series of unrelated individuals to search for statistical associations between the candidate gene polymorphism and the phenotype variation. The relationship between transcript level, protein level or enzyme activity and trait value can be determined and can participate in the validation of candidate genes. Different approaches leading to the characterisation of genes controlling a phenotype are all based on the identification of candidate genes and include different strategies. Several examples of QTLs co-segregating with genes encoding enzymes involved in carbon metabolism have been published.
