PREDICTING MICROEVOLUTIONARY RESPONSES TO DIRECTIONAL SELECTION ON HERITABLE VARIATION
PREDICTING MICROEVOLUTIONARY RESPONSES TO DIRECTIONAL SELECTION ON HERITABLE VARIATION
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DOI：
10.1111/j.1558-5646.1995.tb02236.x
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发表时间：
1995-04-01
期刊：
影响因子：
3.3
通讯作者：
GRANT, BR
中科院分区：
文献类型：
--
作者：
GRANT, PR;GRANT, BR
数量性状在野生环境中的微进化可以从选择和遗传参数的知识进行预测。测试预测需要测量选定群体的后代，这是一个难以满足的要求。我们目前的研究结果达尔文的雀在加拉帕戈斯岛的达芙妮主要满足这一要求。这项研究证明了自然选择的微观进化后果。在1976-1977年的干旱期间，中型地雀（Geospiza fortis）的种群经历了大小选择性死亡;喙深的大型鸟类比小型鸟类生存得更好。在1984年至1986年的另一次干旱期间，种群在喙性状上经历了相反方向的选择。食物供应的变化是喙性状选择的明显原因。正如所有测量性状的高遗传力所预期的那样，选择的效果传递到下一代。一般来说，对这两次选择的进化反应在数量上都有很好的预测。这使我们能够得出结论，在第一近似值，选择的目标被正确地识别，遗传参数被正确地估计。然而，并不是所有的个人特质的反应同样很好地预测。对最大差异的可能原因的研究揭示了环境对某些性状的生长和成年大小的影响所引起的偏差的证据，以及在测量之前对后代的可能选择。这些发现说明了微进化研究中的一个重要假设：父母代和后代在生长到成熟期间所经历的环境是相同的，否则，世代之间测量到的差异可能有部分环境原因，从而对进化对选择的反应给出了误导性的估计。从观察到的选择到长期进化的简单推断可能会低估选择的总力量，如果它在方向上振荡或作用于环境变化。
Microevolution of quantitative traits in the wild can be predicted from a knowledge of selection and genetic parameters. Testing the predictions requires measurement of the offspring of the selected group, a requirement that is difficult to meet. We present the results of a study of Darwin's finches on the Galapagos island of Daphne Major where this requirement is met. The study demonstrates microevolutionary consequences of natural selection.The population of medium ground finches, Geospiza fortis, experienced size-selective mortality during a drought in 1976-1977; large birds with deep beaks survived better than small birds. During another drought, 1984-1986, the population experienced selection in the opposite direction on beak traits. Changes in food supply were the apparent causes of selection on beak traits in both episodes. As expected from the high heritabilities of all measured traits, the effects of selection were transmitted to the next generation. Evolutionary responses to both episodes of selection were quantitatively well predicted in general. This allows us to conclude that, to a first approximation, targets of selection were identified correctly, and genetic parameters were correctly estimated. Nevertheless, not all responses of individual traits were equally well predicted. A search for possible reasons for the largest discrepancies revealed evidence of bias caused by environmental effects on growth and adult size of some traits, as well as possible selection on the offspring generation before their measurement.These findings illustrate an important assumption in the study of microevolution: that the environments experienced during growth to maturity by the parental and offspring generations are the same, for otherwise a measured difference between generations may have a partly environmental cause, thereby giving a misleading estimate of the evolutionary response to selection. Simple extrapolations from observed selection to long-term evolution may underestimate the total force of selection involved if it oscillates in direction or acts on the environmental variance.