Effects of marker-assisted selection under different initial frequency of QTL favorable allele.

A ten-generation continuous selection experiment on a single trait in a closed population was carried out by stochastic simulation. It assumed that the trait was controlled by polygenes and a single autosomal bi-allelic marked quantitative trait locus (QTL). Individual breeding values were estimated through animal model marker-assisted best linear unbiased prediction (MB-LUP), and breeding animals were selected according to their breeding values. The effects of three levels initial frequencies of QTL favorable allele on marker-assisted selection (MAS) were studied. The results showed that it would gain higher genetic response when implementing MAS on those traits with lower initial frequency of QTL favorable allele. When the initial frequency of QTL favorable allele was low, although the generation number required for fixing QTL favorable allele in the population would be lengthened, its frequency would be increased faster. However, the initial frequency of QTL favorable allele had little effects on the inbreeding rates.