Wang Yu, Segelke Dierck, Emmerling Reiner, Bennewitz Jörn, Wellmann Robin
Institute of Animal Science, University of Hohenheim, 70593 Stuttgart, Germany
Vereinigte Informationssysteme Tierhaltung w.V., 27283 Verden, Germany.
G3 (Bethesda). 2017 Dec 4;7(12):4009-4018. doi: 10.1534/g3.117.300272.
The long-term performance of different selection strategies was evaluated via simulation using the example of a local cattle breed, German Angler cattle. Different optimum contribution selection (OCS) approaches to maximize genetic gain were compared to a reference scenario without selection and truncation selection. The kinships and migrant contribution (MC) were estimated from genomic data. Truncation selection achieved the highest genetic gain but decreased diversity considerably at native alleles. It also caused the highest increase in MCs. Traditional OCS, which only constrains kinship, achieved almost the same genetic gain but also caused a small increase of MC and remarkably reduced the diversity of native alleles. When MC was required not to increase and the increase of kinship at native alleles was restricted, the MC levels and the diversity at native alleles were well managed, and the genetic gain was only slightly reduced. However, genetic progress was substantially lower in the scenario that aimed to recover the original genetic background. Truncation selection and traditional OCS selection both reduce the genetic originality of breeds with historical introgression. The inclusion of MC and kinship at native alleles as additional constraints in OCS showed great potential for conservation. Recovery of the original genetic background is possible but requires many generations of selection and reduces the genetic progress in performance traits. Hence, constraining MCs at their current values can be recommended to avoid further reduction of genetic originality.
以当地牛品种德国安格勒牛为例，通过模拟评估了不同选择策略的长期性能。将不同的优化贡献选择（OCS）方法与不进行选择和截断选择的参考方案进行比较，以最大化遗传增益。根据基因组数据估计亲缘关系和迁移贡献（MC）。截断选择实现了最高的遗传增益，但显著降低了本地等位基因的多样性。它还导致MC的增加幅度最大。仅限制亲缘关系的传统OCS实现了几乎相同的遗传增益，但也导致MC略有增加，并显著降低了本地等位基因的多样性。当要求MC不增加且本地等位基因的亲缘关系增加受到限制时，MC水平和本地等位基因的多样性得到了很好的管理，遗传增益仅略有降低。然而，在旨在恢复原始遗传背景的方案中，遗传进展显著较低。截断选择和传统OCS选择都会降低具有历史基因渗入的品种的遗传原始性。在OCS中纳入MC和本地等位基因的亲缘关系作为额外的限制条件显示出巨大的保护潜力。恢复原始遗传背景是可能的，但需要多代选择，并且会降低性能性状的遗传进展。因此，建议将MC限制在其当前值，以避免遗传原始性的进一步降低。
