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 b...本实验针对日本鹌鹑（Japanese quail）的43日龄体重与存活性状，开展了多层选择（multilevel selection）效应的对比研究，试验个体分别饲养于亲缘组（kin group, K）或随机组（random group, R）中。多层选择可显著降低鹌鹑死亡率（亲缘组为6.6%，随机组为8.5%），同时提升其体重（亲缘组为1.30 g/MG，随机组为0.13 g/MG），亲缘组的选择响应幅度较随机组高出一个数量级。由此可见，多层选择可有效抑制有害社交互动，进而改善体重增长情况。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响应机制。基于估算得到的遗传参数，群体选择始终优于其他任何形式的多层选择组合。进一步研究显示，若将20%的权重分配至群体组分，无论群体构成如何，采用多层选择即可获得接近最优的试验结果。因此在自然环境中，多层选择得以发生的条件为……