Kang KS, Bila AD, Lindgren D, Choi WY
Predicted drop in gene diversity over generations in the population where the fertility varies among individuals
Silvae Genetica: 2001 50:200-205
Gene diversity and inbreeding of seed crop over generations were derived and predicted as a function of fertility variation and population sizes in forest tree populations. Gene diversity was calculated in terms of group coancestry. Fertility differences were described by sibling coefficient, which is the probability that two genes originate from the same parent, compared to a situation where all parents give rise to the same number of offspring. Fertility data were collected in a finite population, and calculations were made for the case of a constant breeding population size. The change of status number could be associated with the sibling coefficient. Predictions over five generations showed that group coancestry and inbreeding accumulated fast at the first early shifts. Relative status number declined very fast over generations. The increase of inbreeding and group coancestry was accelerated by fertility variation, and the accumulation was slightly faster and higher if fertility of both genders varied than if maternal fertility was kept constant. Gene diversity decreased faster if fertility variation was large, and maintained higher if the effective population size was reasonably large. Breeding programs that use closely related genotypes lead to the decrease of effective number (i.e., drop in gene diversity) over generations and do not provide a sustainable long-term breeding strategy.
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