Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, D-70599 Stuttgart, Germany.
Genet Sel Evol. 2012 Nov 15;44(1):34. doi: 10.1186/1297-9686-44-34.
In recent decades, local varieties of domesticated animal species have been frequently crossed with economically superior breeds which has resulted in considerable genetic contributions from migrants. Optimum contribution selection by maximizing gene diversity while constraining breeding values of the offspring or vice versa could eventually lead to the extinction of local breeds with historic migration because maximization of gene diversity or breeding values would be achieved by maximization of migrant contributions. Therefore, other objective functions are needed for these breeds.
Different objective functions and side constraints were compared with respect to their ability to reduce migrant contributions, to increase the genome equivalents originating from native founders, and to conserve gene diversity. Additionally, a new method for monitoring the development of effective size for breeds with incomplete pedigree records was applied. Approaches were compared for Vorderwald cattle, Hinterwald cattle, and Limpurg cattle. Migrant contributions could be substantially decreased for these three breeds, but the potential to increase the native genome equivalents is limited.
The most promising approach was constraining migrant contributions while maximizing the conditional probability that two alleles randomly chosen from the offspring population are not identical by descent, given that both descend from native founders.
近几十年来，家养动物的地方品种经常与经济优势品种杂交，这导致了大量移民的基因贡献。通过最大化基因多样性来实现最优的贡献选择，同时限制后代的繁殖值，或者反之，最终可能导致具有历史迁徙的地方品种灭绝，因为最大化基因多样性或繁殖值将通过最大化移民的贡献来实现。因此，这些品种需要其他的目标函数。
不同的目标函数和边约束条件被比较，以了解它们减少移民贡献、增加源自本地祖先的基因组等效物以及保护基因多样性的能力。此外，还应用了一种新的方法来监测具有不完全谱系记录的品种有效大小的发展。这些方法在 Vorderwald 牛、Hinterwald 牛和 Limpurg 牛中进行了比较。这三个品种的移民贡献可以大幅减少，但增加本地基因组等效物的潜力有限。
最有前途的方法是在限制移民贡献的同时，最大化条件概率，即从后代群体中随机选择的两个等位基因不是由本地祖先随机遗传而来的概率。
