LIFE HISTORY TRAITS AND NATURAL SELECTION FOR SMALL BODY SIZE IN A POPULATION OF DARWIN'S FINCHES
LIFE HISTORY TRAITS AND NATURAL SELECTION FOR SMALL BODY SIZE IN A POPULATION OF DARWIN'S FINCHES
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达尔文雀种群的生活史特征和小体型的自然选择
DOI：
10.1111/j.1558-5646.1984.tb00314.x
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发表时间：
1984
期刊：
影响因子：
3.3
通讯作者：
P. Grant
中科院分区：
文献类型：
--
作者：
T. Price;P. Grant
数量遗传学的理论和方法在生活史研究中的应用使得人们关注生活史性状之间的表型和遗传协方差的测量（Stearns，1980，1982 a，1982 b;丁格尔和Hegmann，1982 p.231 -244; Etges，1982; Giovannet al.，1982; Hegmann和丁格尔，1982; Lande，1982; Rose，1983）。这些协方差是描述这些性状进化的理论模型中的基本参数。遗传协方差的估计是基于亲属之间的相似性。遗传协方差通常是在实验室中估计的，在实验室中，环境是受控的，死亡的主要原因通常是衰老。协方差在自然界中不太容易估计，因为环境相关性可能在幅度上波动很大，并随着条件的变化而变化（Lande，1982年），而且死亡原因也各不相同。因此，生活史性状之间的遗传协方差的直接估计将变化（Giovannet al.，1982; Stearns，1982 a，1982 b）。在本文中，我们采用了一种替代的，间接的方法来估计自然种群的生活史性状之间的协方差。它依赖于在两个生活史阶段对形态特征的选择的测量，以及假设每个阶段的适应性的大部分差异是由于选择作用的特征的差异。两个生活史性状，如在两个给定的发育阶段存活的概率，如果它们每个都由相同的形态特征或特征决定，则可以说是共变的。协方差的大小和方向可以从选择的大小和方向定性地估计。此外，如果发现形态特征是高度可遗传的，则可以推断这两个生活史特征在遗传上是共变的。Boag和Grant（1981）观察到，在达尔文的中型地雀（Geospiza fortis）种群中，强烈的自然选择倾向于大喙和体型，这与干旱期间的成年死亡率有关。死亡的主要原因是饥饿，形态上的差异生存至少部分反映了环境中剩余食物的差异处理能力（Boag和Grant，1981年）。由于大小的措施是高度可遗传的，与一些高度可重复的措施，如喙的深度具有超过.8的遗传率（博格和格兰特，1978年;博格，1983年），成人生存的概率就大小的特点，预计也是一个高度可遗传的特点，提供成人死亡率基于大小的结果，从相同的一般原因，在不同的世代。在本文中，我们考虑在生命周期的其他阶段的身体大小的选择的可能性。具体来说，我们要问的是，定向选择是一个具有长期进化后果的孤立事件，还是在生命周期的其他阶段被有利于小体型的选择所平衡？为了回答这个问题，我们研究的可能性选择与青少年死亡率的身体大小。如果在这个生命史阶段发现了选择，我们就可以遵循上面的推理。特别是，我们可以认为幼年生存的可能性是可遗传的，并且在遗传上与成年生存的可能性呈负相关。在此过程中，我们假设
Application of the theory and methods of quantitative genetics to life history studies has led to a focus on the measurement of phenotypic and genetic covariances between life history traits (Stearns, 1980, 1982a, 1982b; Dingle and Hegmann, 1982 p. 231-244; Etges, 1982; Giesel et al., 1982; Hegmann and Dingle, 1982; Lande, 1982; Rose, 1983). These covariances are the essential parameters in theoretical models describing the evolution of such traits. Estimation of genetic covariance is based on the resemblance between relatives. Genetic covariances have usually been estimated in the laboratory where the environment is controlled and the main cause of mortality is often senescence. Covariances are less easy to estimate in nature because environmental correlations are likel.y to fluctuate greatly in magnitude and sign with changing conditions (Lande, 1982) and because causes of mortality also vary. Thus direct estimates of genetic covariances between life history traits will vary (Giesel et al., 1982; Stearns, 1982a, 1982b). In this paper we adopt an alternative, indirect, approach to estimating covariances between life history traits in natural populations. It depends on the measurement of selectioni on a morphological character at two life history stages, and the assumption that much of the variance in fitness at each stage is due to variance in the character or characters upon which selection acts. Two life history traits, such as probability of survival over two given developmental stages, may be said to covary if they are each determined by the same morphological character or characters. The size and direction of the covariance can be qualitatively estimated from the magnitude and directions of selection. Further, if the morphological character is found to be highly heritable it can be inferred that the two life history traits covary genetically. Boag and Grant (1981) observed intense natural selection favoring large beak and body size in a population of Darwin's Medium Ground finches, Geospiza fortis, associated with adult mortality during a drought. The main cause of mortality was starvation, and differential survival with respect to morphology was at least partly a reflection of differential handling ability of the foods remaining in the environment (Boag and Grant, 1981). Since size measures are highly heritable, with some highly repeatable measures such as beak depth having heritabilities of over .8 (Boag and Grant, 1 978; Boag, 1983), the probability of adult survival with respect to size characters is also expected to be a highly heritable character, provided that adult mortality based on size results from the same general causes in different generations. In this paper we consider the possibility of selection on body size at other stages of the life cycle. Specifically we ask, was the directional selection an isolated event with long term evolutionary consequences, or is it balanced by selection favoring small body size at other stages of the life cycle? To answer this question we examine the possibility of selection on body size associated with juvenile mortality. If selection at this life history stage is found we can follow the reasoning developed above. In particular we can argue that probability ofjuvenile survival is heritable, and genetically negatively covaries with pirobability of adult survival. In doing so, we assume juvenile
果蝇寿命延长的遗传学。
DOI：
10.1002/bies.950110505
发表时间：
1989
期刊：
BioEssays : news and reviews in molecular, cellular and developmental biology
影响因子：
--
作者：
Rose,MR
通讯作者：
Rose,MR