Data from: Multilevel selection with kin and non-kin groups, experimental results with Japanese quail (Coturnix japonica)

An experiment was conducted comparing multilevel selection in Japanese quail for 43 days weight and survival with birds housed in either kin (K) or random (R) groups. Multilevel selection significantly reduced mortality (6.6% K vs. 8.5% R) and increased weight (1.30 g/MG K vs. 0.13 g/MG R) resulting in response an order of magnitude greater with Kin than Random. Thus multilevel selection was effective in reducing detrimental social interactions, which contributed to improved weight gain. The observed rates of response did not differ significantly from expected, demonstrating that current theory is adequate to explain multilevel selection response. Based on estimated genetic parameters, group selection would always be superior to any other combination of multilevel selection. Further, near optimal results could be attained using multilevel selection if 20% of the weight was on the group component regardless of group composition. Thus in nature the conditions for multilevel selection to be effective in bringing about social change maybe common. In terms of a sustainability of breeding programs, multilevel selection is easy to implement and is expected to give near optimal responses with reduced rates of inbreeding as compared to group selection, the only requirement is that animals be housed in kin groups.

本实验针对日本鹌鹑的43日龄体重与存活率开展多层选择（multilevel selection）对比研究，将实验鹌鹑分为亲缘组（K，kin）与随机组（R，random）进行饲养。结果表明，多层选择可显著降低鹌鹑死亡率（亲缘组6.6% vs. 随机组8.5%），同时提升其体重（亲缘组1.30 g/MG vs. 随机组0.13 g/MG），且亲缘组的选育响应幅度较随机组高出一个数量级。由此可见，多层选择能够有效抑制有害社会互作，进而改善增重效果。观测得到的响应速率与理论预期值无显著差异，证明现有理论足以解释多层选择的选育响应规律。基于估算得到的遗传参数，群体选择（group selection）始终优于其他任何形式的多层选择组合方案。此外，若将20%的权重赋予群体组分，无论群体构成如何，采用多层选择即可获得接近最优的选育效果。因此在自然环境中，多层选择能够有效推动社会性状改变的条件可能普遍存在。从育种计划的可持续性角度来看，相较于群体选择，多层选择易于实施，且可在降低近交速率的同时获得接近最优的选育响应，其唯一实施要求为实验动物需以亲缘群体的形式进行饲养。