The Effects Of Linkage Disequlibrium On The Additive And Dominance Variances In A Random Mating Small Population

Abstract

In a random ınating small population components of genetic variance of a guantitative trait are studied as a stochastic process över discrete generations for a two-locus dominance model. Siugle-locus and two locus terms in the expected values of the components are defined and solved by using the marginal and simultaneous distributions of two locus gene freguencies.Theoretical expectations of the variances are obtained for a genetic system simulated previously. These expectations are compared with the results in simulation. A faster decrease in genetic variance components is observed in simulation. Probable reasons for this are discussed.In theoretical expecetations the effect of linkage diseguilibrium on both additive and dominance variances is found to be significant. Even in the case of initial linkage eguilibrium there is an increase in dominance variance in early generations since some expectations related to the joint distributions of two genes are not zero in replicate lines.

The Effects Of Linkage Disequlibrium On The Additive And Dominance Variances In A Random Mating Small Population

“…So in theoretical expectations two step sampling which is the case in most agricultural populations was a consideration was done in a previous study on not carried out. Such additive variance and approach was found to be better than the classical one is, although simulation results stül showed faster decrease (Kavuncu, 1984). It may be worthwhile to study whether the sampling step to get the parents of next generation may have non-trivial effects value of dominance variance as well.…”