Department of Animal Science, University of California, Davis, California, USA.
Theor Appl Genet. 1970 Jan;41(4):164-73. doi: 10.1007/BF00277619.
Response to upward selection in 10 replicate lines was linear through 15 generations, had slowed considerably in many lines by generation 23 and continued in other lines through 30 generations. The lines tended to group into those which responsed slowly during early generations and continued to respond through later generations and those which gave rapid early response and very low response later coupled with marked reduction in fitness. Response to downward selection was similar for 3 replicate lines but only 50% as great as that for the high lines. Response declined more rapidly in the low lines due to reduced fitness, declining selection differentials and a marked drop in phenotypic variance.
在 10 个重复系中，对向上选择的反应在 15 代内是线性的，到第 23 代时许多系的反应速度明显减慢，而在其他系中则持续到第 30 代。这些系往往分为两类：一类在早期反应缓慢，而在后期持续反应；另一类则在早期快速反应，后期反应非常低，同时适应度显著降低。对 3 个重复系的向下选择的反应是相似的，但只有高系的一半。由于适应度降低、选择差下降和表型方差显著下降，低系的反应下降得更快。
