Marker assisted selection. Most economically
important traits in animal production are of a
quantitative nature and are affected by a large
number of genes (loci), a few of which have major
effects, while the majority have small effects (Le
Roy et al., 1990; Andersson et al., 1994). If a gene
(locus) with a major effect can be identified, and
if a molecular test can be designed, animals’
genotypes at the locus can be used for selection.
In other cases, a chromosomal region close to the
gene of interest may be identified and used as a
marker