Meuwissen T H, Sonesson A K
DLO-Institute for Animal Science and Health, Lelystad, The Netherlands.
J Anim Sci. 1998 Oct;76(10):2575-83. doi: 10.2527/1998.76102575x.
In a breeding scheme, the aim is high rates of genetic gain with limited inbreeding. A dynamic selection rule is developed that maximizes selection response in populations with overlapping generations. The rule maximizes the genetic merit of selected animals while limiting the average relationship of the population after the current round of selection. The latter is shown to limit the contribution of the current population to the future inbreeding. The rule accounts for the selection of some candidates during previous selection rounds and for the expected future contributions of the selection candidates. Inputs for the rule are the BLUP breeding values and ages of selection candidates, the relationship matrix of all animals, and contributions of animals during previous selection rounds. Output is the optimal number of offspring for each candidate. Computer simulations of dairy cattle nucleus schemes showed that predefined rates of inbreeding were actually achieved, without compromising long-term selection response, at least up to 20 yr of selection. At the same rates of inbreeding, the dynamic selection rule obtained up to 44% more genetic gain than direct selection for BLUP breeding values. The advantage of the dynamic rule over BLUP selection decreased with increasing population sizes and with greater predefined rates of inbreeding. Consequently, the dynamic rule should be especially useful in small selection schemes in which relatively low rates of inbreeding are desired.
在育种计划中，目标是在有限的近亲繁殖情况下实现高遗传进展率。开发了一种动态选择规则，该规则可使重叠世代群体中的选择反应最大化。该规则在最大化所选动物的遗传价值的同时，限制了当前一轮选择后群体的平均亲缘关系。结果表明，后者限制了当前群体对未来近亲繁殖的贡献。该规则考虑了前几轮选择中一些候选个体的选择情况以及选择候选个体未来的预期贡献。该规则的输入包括最佳线性无偏预测（BLUP）育种值、选择候选个体的年龄、所有动物的亲缘关系矩阵以及前几轮选择中动物的贡献。输出是每个候选个体的最佳后代数量。奶牛核心群计划的计算机模拟表明，实际实现了预定的近亲繁殖率，且不影响长期选择反应，至少在长达20年的选择期内如此。在相同的近亲繁殖率下，动态选择规则比直接选择BLUP育种值获得的遗传进展多44%。随着群体规模的增加和预定近亲繁殖率的提高，动态规则相对于BLUP选择的优势会降低。因此，动态规则在希望近亲繁殖率相对较低的小型选择计划中应特别有用。
