A population genetics model of linkage disequilibrium in admired populations

Understanding linkage disequilibrium (LD) created in admired population and the rate of decay in the disequilibrium over evolution is an important sub ject in population genetics theory and in disease gene mapping in human pop ulations. The present study represents the theoretical investigation of eff ects of gene frequencies, levels of LD and admixture proportions of donor p opulations on the evolutionary dynamics of the LD of the admired population . We examined the conditions under which the admired population reached lin kage equilibrium or the peak level of the LD. The study reveals the inappro priateness in approximating the dynamics of the LD generated by population admixture by the commonly used formula in literature. An appropriate equati on for the dynamics is proposed. The distinct feature of the newly suggeste d formula is that the value of the nonlinear component of the LD remains co nstant in the first generation of the population evolution. Comparison betw een the predicted disequilibriun dynamics shows that the error will be caus ed by using the old formula, and thus resulting in a misguidance in using t he evolutionary information of the admired population in gene mapping.