Marker-assisted selection for a sex-limited character in a nucleus breeding population.
The benefits of marker-assisted selection were examined by simulation of an adult multiple ovulation and embryo transfer nucleus breeding scheme. Animals were either typed for two polymorphic marker loci, 20 centimorgans apart, flanking a single biallelic quantitative trait locus and were evaluated using a model accounting for marker information, or animals were not typed but were evaluated by a conventional BLUP animal model. Selection was for a single trait measured on females, and each dam had 4 sons and 4 daughters. Nucleus foundation animals were chosen from a base population in linkage equilibrium. With the favorable allele at an initial frequency of 0.5, marker-assisted selection substantially increased responses at the quantitative trait locus but reduced the polygenic responses. Cumulative genetic gain increased by up to 3, 9, 12, and 6% after one, two, three, and six generations of selection, respectively. If the favorable allele was initially rare (frequency of 0.1), the merits of marker-assisted selection were even more pronounced (genetic gains increased by up to 9, 19, 24 and 15%, respectively). The superiority of marker-assisted selection over conventional BLUP increased when a restriction was placed on selection of full brothers and decreased when variance of the quantitative trait locus used in the evaluation model was overestimated.
Station de Génétique Quantitative et Appliquée, Centre de Jouy-en-Josas, France.
J
J
Ruane
J J
JJ
Colleau
D000483:Alleles; D000818:Animals; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000235:genetics*; D004624:Embryo Transfer; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D008297:Male; D008957:Models, Genetic; D010062:Ovulation Induction
D005819:Genetic Markers