Institute of Animal Genetics, Edinburgh, Scotland.
Theor Appl Genet. 1976 May;48(3):101-4. doi: 10.1007/BF00281652.
The effect of t ' generations of reverse selection after t generations of forward selection can be described by expressing the change in the metric mean resulting from reverse selection (R) interms ofthe change in the metric mean due to the previous forward selection (Δx). An additive model of artificial selection in a population of effective size N with no natural selection has been considered.If reverse selection is continued for as many generations as the previous forward selection (t'=t), then the ratio R/Δx equals 1 - F where F is the inbreeding coefficient for a neutral locus at generation t and is estimated as [1-(1-1/2N)(t)]. The result of a single generation of reverse selection (t'=1) following t generations of forward selection can be described in terms of the ratio NR1/ηDx where R1 is the response to the first generation of reverse selection. The value of NR1/Δx is expected to be (1-F) /2F.For any period of reverse selection following any period of forward selection, the value of R/Δx never exceeds t '/t, and tends to decrease exponentially from this value as t increases.
经过 t 代正向选择后，经过 t'代反向选择的效果可以通过表示由反向选择引起的度量均值的变化（R）来描述，其中度量均值的变化是由于先前的正向选择（Δx）引起的。在没有自然选择的有效大小为 N 的群体中，已经考虑了人工选择的加性模型。如果反向选择持续的代数与之前的正向选择一样多（t'=t），则 R/Δx 的比值等于 1 - F，其中 F 是世代 t 中性基因座的近交系数，可通过[1-(1-1/2N)(t)]进行估计。在经过 t 代正向选择后，经过一代反向选择（t'=1）的结果可以用 NR1/Δx 的比值来描述，其中 R1 是第一代反向选择的响应。NR1/Δx 的值预计为（1-F）/2F。对于任何一段时间的反向选择，无论其前面有多长时间的正向选择，R/Δx 的值都不会超过 t'/t，并且随着 t 的增加，它会从这个值呈指数级下降。
Zotero 插件