Genomics and the genetic improvement of broiler chicken

Thanks to the efforts of many research groups worldwide, a wealth of information has been produced in the last decade concerning the chicken genome. This is primarily information about the genetic map, the basic and invaluable tool used to search for quantitative trait loci (QTL), but there are also physical maps of the genome, and more recently its complete sequencing has been accomplished. Together with this progress in the field of maps genomics, more recent advances have been made in functional genomics, with the sequencing of large numbers of expressed sequence tags (EST) representing the expressed genes from which DNA chips can be designed. These can be used to define networks of genes involved in the expression of phenotypic traits. The combination of data on QTL and on gene expression will help scientists to understand the molecular mechanisms involved in the expression of variations in traits of economic importance and provide new tools for the selection of chicken, through marker-assisted selection (MAS).