Weber K E
Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138.
Genetics. 1990 Jul;125(3):579-84. doi: 10.1093/genetics/125.3.579.
The effect of population size on selection response was investigated with replicated selection lines of 40, 200 and 1000 selected parents, using Drosophila melanogaster homozygous for the mutant raised. Selection for increased wing-tip height was carried out for 55 generations, with an average selection intensity of 0.6 standard deviation. The rank order of responses in the seven individual lines was significantly in order of population size, and the variance of response among lines showed a significant effect of population size. The final mean responses (selected - controls, +/- standard errors) in the three treatments, in order of increasing population size, were 8.6 +/- 1.8 mils (three small lines), 15.1 +/- 1.3 mils (two medium lines), and 19.8 +/- 1.5 mils (two large lines). The differences between treatments seem to have emerged too rapidly to be the result of mutations, and are probably due mainly to the utilization of existing variation with greater efficiency by selection in larger populations.
利用饲养的突变型纯合黑腹果蝇，通过对40、200和1000个选定亲本进行重复选择品系，研究了群体大小对选择反应的影响。对增加翅尖高度进行了55代的选择，平均选择强度为0.6个标准差。七个个体品系的反应排名顺序按群体大小显著排列，品系间反应的方差显示出群体大小的显著影响。三种处理的最终平均反应（选定组-对照组，±标准误），按群体大小增加的顺序，分别为8.6±1.8密耳（三个小群体品系）、15.1±1.3密耳（两个中等群体品系）和19.8±1.5密耳（两个大群体品系）。处理之间的差异似乎出现得太快，不可能是突变的结果，可能主要是由于在较大群体中选择能更有效地利用现有变异。
