Animal breeders currently assume that economically important traits
such as growth, carcass composition and reproductive performance
are controlled by an infinite number of genes each of infinitessimal
effect. Although this model is known to be unrealistic, it has
successfully underpinned the genetic improvement of livestock,
including pigs, over recent decades. A map of the pig genome would
allow the development of more realistic models of the genetic
control of economic traits and the ultimately the identification
of the major trait genes. This would allow the development of
more efficient marker assisted selection which may be of particular
value for traits such as disease resistance and meat quality.
