GENE FLOW AND POPULATION DIFFERENTIATION
GENE FLOW AND POPULATION DIFFERENTIATION
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DOI：
10.1126/science.179.4070.243
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发表时间：
1973-01-01
期刊：
影响因子：
56.9
通讯作者：
ENDLER, JA
中科院分区：
文献类型：
--
作者：
ENDLER, JA
有许多可能的选择和基因流动的空间模式可以产生给定的倾斜面结构；在试图用模型来解释给定的自然倾斜面之前，必须弄清自然选择和基因流动的实际地理位置。实验和理论模型的结果表明，如果选择梯度相对均匀，尽管存在相当大的基因流动，但局部分化是可能的。环境梯度的不规则性增加了克隆对基因流动影响的敏感性，与移民和接收移民的德米人之间基因频率差异的增加成比例。不一定要有剧烈的空间环境变化才能发生明显的分化。在某些情况下，即使是一个温和的环境梯度，也可以沿着遗传上连续的DEME系列引起显着的空间差异；这种环境差异可能低于实地研究的实际分辨率极限。如果环境梯度是平滑的，基因流动的任何不对称都不会导致去分化；它只是改变了分化区域之间过渡区的位置，而不是在没有不对称的情况下预期的位置。因此，基因、基因型或变异频率的突然地理差异不应被解释为斜坡最陡峭部分附近环境变化的证据；也不应被解释为地理障碍、明显的环境差异或在没有其他证据来源的情况下不同群体之间存在性别隔离的证据。基因流在种群沿环境梯度的分化中可能并不重要。
There are many possible spatial patterns of selection and gene flow that can produce a given cline structure; the actual geography of natural selection and gene flow must be worked out before an attempt is made to explain a given natural cline in terms of a model.The results of experimental and theoretical models show that it is possible for local differentiation to evolve parapatrically in spite of considerable gene flow if the selection gradients are relatively uniform. Irregularities in environmental gradients increase the sensitivity of clines to the effects of gene flow in proportion to the increase in the differences in gene frequencies between the emigrants and the demes receiving the immigrants. It is not necessary for a sharp spatial environmental change to be present for distinct differentiation to occur. In some cases even a gentle environmental gradient can give rise to marked spatial differentiation along a genetically continuous series of demes; such environmental differences may be below the practical limits of resolution in field studies. Any asymmetry in gene flow does not lead to dedifferentiation if the environmental gradient is smooth; it merely shifts the position of the transition zone between the differentiated areas from that which would be expected if there were no asymmetry. Abrupt geographic differences in gene, genotype, or morph frequencies should not, therefore, be interpreted as evidence for environmental changes in the immediate vicinity of the steepest part of the cline; neither should they be interpreted as evidence for geographic barriers, sharp environmental differences, or sexual isolation among the differentiated groups of populations when there are no other sources of evidence for these phenomena. Gene flow may be unimportant in the differentiation of populations along environmental gradients.