Future directions: Finding candidate genes & cloning
QTL are usually rather large, often undefined, regions of the chromosome which can encompass many genes. Finding a candidate gene or cloning the specific gene associated with the trait of interest can give more information about the function of the gene.
While this isn’t necessary for MAB, it can make it more efficient by narrowing down the target region to be selected for and knowing the function can make predictions about its behavior in other lines more accurate. However, it is a difficult process, and only a small number of plant genes have been cloned to date.
For a good review, see Salvi and Tuberosa 2005.