ABSTRACT
Genes Affecting MQ .................................................................................... 315 10.7 General Conclusions ..................................................................................... 317 References .............................................................................................................. 318
To date, most genetic progress in quantitative traits in livestock has been made by selection on phenotypic information, or on estimates of breeding values derived from such phenotypic information, without any knowledge of the genes underlying the genetic variation. The number of these genes, and their wider properties, such as the magnitude of their effects, their frequencies, and interactions between them, have been largely ignored in this quantitative genetic approach. The genetic architecture of traits of interest has essentially been treated as a “black box,” but, nevertheless, substantial rates of genetic improvement have been achieved (e.g., Dekkers and Hospital 2002; Hill 2014). However, further improvements are necessary, alongside a widening of selection goals. With advances in molecular genetic tools, the arsenal available to breeders is being revolutionized, allowing them to study the genetic makeup of individuals at the DNA level.
