[The effects of longterm selection on the genetic structure of populations--a simulation study. II. The effects of selection on genetic variances].
Monte Carlo simulation has been done to study the effects of longterm artificial selection on genetic variances under additive, dominant, and over-dominant models. The effects of population size, linkage, and heritability have been considered. Just as under the additive model, the additive variance under the dominant and over-dominant models has also been decomposed into three components which represent changes in gene frequencies (VT), departure from Hardy-Weinberg equilibrium (VHW) and from linkage equilibrium (VLD) respectively. These present a resonable approach to study the association among multiple genes. In small populations, genetic variance fluctuates wildly over generations and replicates due to the establishment of linkage disequilibrium. Rapid decrease of VT observed. Intense linkage retained a greater additive variance in the small populations while slowing down responses, which makes it difficult to predict responses during longterm selection.
Yang
Z H
ZH
Department of Animal Sciences, Gansu Agricultural University.
Wu
Z X
ZX
Zhang
Y
Y
D000818:Animals; D003198:Computer Simulation; D014644:Genetic Variation; D006801:Humans; D008957:Models, Genetic; D012641:Selection, Genetic