EFFICIENCY OF TRUNCATION SELECTION
EFFICIENCY OF TRUNCATION SELECTION
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DOI：
10.1073/pnas.76.1.396
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发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
KIMURA, M
中科院分区：
文献类型：
--
作者：
CROW, JF;KIMURA, M
截断选择是定向选择最有效的形式。当对其进行修改以使适应度在所选字符值的 1 或 2 SD 范围内线性增加时，效率会降低，但不会很大。当截断选择与适应度与字符值严格成正比的系统进行比较时，截断选择的相对效率由f(c)/σ给出，其中f(c)是截断点和σ处频率分布的纵坐标。是角色的 SD。对于影响果蝇活力的突变，截短选择或合理偏离可以大大减少突变负荷。这可能是调和此类基因的极高突变率与小突变负荷的一种方法。由于这些突变的近似可加性，具有方向选择的截断模型适合这种情况。值得怀疑的是，这个简单的模型是否可以应用于所有影响适应度的基因，对于这些基因来说，负相关的成分之间存在中间最优和拮抗选择。大自然是否对这种行为进行排序和截断，或者近似这种行为，是一个经验问题，有待回答。
Truncation selection is the most efficient form of directional selection. When this is modified so that the fitness increases linearly over a range of 1 or 2 SD of the value of the selected character, the efficiency is reduced, but not greatly. When truncation selection is compared to a system in which fitness is strictly proportional to the character value, the relative efficiency of truncation selection is given by f(c)/.sigma., in which f(c) is the ordinate of the frequency distribution at the truncation point and .sigma. is the SD of the character. For mutations affecting viability in Drosophila, truncation selection or reasonable departures therefrom can reduce the mutation load greatly. This may be one way to reconcile the very high mutation rate of such genes with a small mutation load. The truncation model with directional selection is appropriate for this situation because of the approximate additivity of these mutations. It is doubtful that this simple model can be applied to all genes affecting fitness, for which there are intermediate optima and antagonistic selection among components with negative correlations. Whether nature ranks and truncates, or approximates this behavior, is an empirical question, yet to be answered.