NATURAL SELECTION AND INHERITANCE OF BREEDING TIME AND CLUTCH SIZE IN THE COLLARED FLYCATCHER
NATURAL SELECTION AND INHERITANCE OF BREEDING TIME AND CLUTCH SIZE IN THE COLLARED FLYCATCHER
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颈鹟繁殖时间和产窝大小的自然选择与遗传
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发表时间：
2003
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通讯作者：
Juha Merilä
中科院分区：
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作者：
Ben C. Sheldon;Ben C. Sheldon;L. Kruuk;Juha Merilä
自由生活种群中生物体的许多特征似乎处于定向选择之下，具有加性遗传变异，但对选择没有进化反应。鸟类的繁殖时间和窝卵数是经常被引用的例子。我们报告的遗传分析，并选择，这些特征在一个长期的研究野生种群的领蝇Ficedula albicollis。我们使用混合模型分析与REML估计（“动物模型”），以充分利用复杂的多代家系中的信息。产蛋日期的遗传力，但不是窝卵数，低于以前估计使用父母-后代回归，虽然这两个性状有大量的加性遗传方差的证据（H2 = 0.19和0.29，分别）。产蛋日期和窝卵数在遗传上呈负相关（rA =-0.41 ± 0.09），这意味着对其中一个性状的选择会导致另一个性状的相关反应，但几乎没有证据表明任何一个性状的进化会受到与其他表型性状相关性的限制。对雌性的这些性状的选择分析表明，在表型水平上，早期育种的定向繁殖力选择是一致的（β = −0.28 ± 0.03），但几乎没有证据表明育种时间上的稳定选择。我们没有发现任何证据表明，离合器的大小是独立的选择。根据动物模型估计的产蛋日期的育种值对繁殖力选择的分析表明，选择直接作用于育种时间的加性遗传方差（β =-0.20 ± 0.04），但不影响窝卵数（β = 0.03 ± 0.05）。与此相反，通过成年雌性存活率对产蛋日期的选择在年份之间波动，而对表型（负）和育种值（正）的选择则相反。因此，我们的数据表明，任何进化的选择产卵日期的反应是部分限制潜在的生活史权衡，并说明了困难，使用纯粹的表型措施和不完整的健身估计，以评估进化的生活史权衡。我们讨论了一些困难与理解自然种群的产卵日期和窝卵数的演变。
Abstract Many characteristics of organisms in free-living populations appear to be under directional selection, possess additive genetic variance, and yet show no evolutionary response to selection. Avian breeding time and clutch size are often-cited examples of such characters. We report analyses of inheritance of, and selection on, these traits in a long-term study of a wild population of the collared flycatcher Ficedula albicollis. We used mixed model analysis with REML estimation (“animal models”) to make full use of the information in complex multigenerational pedigrees. Heritability of laying date, but not clutch size, was lower than that estimated previously using parent-offspring regressions, although for both traits there was evidence of substantial additive genetic variance (h2 = 0.19 and 0.29, respectively). Laying date and clutch size were negatively genetically correlated (rA = −0.41 ± 0.09), implying that selection on one of the traits would cause a correlated response in the other, but there was little evidence to suggest that evolution of either trait would be constrained by correlations with other phenotypic characters. Analysis of selection on these traits in females revealed consistent strong directional fecundity selection for earlier breeding at the level of the phenotype (β = −0.28 ± 0.03), but little evidence for stabilising selection on breeding time. We found no evidence that clutch size was independently under selection. Analysis of fecundity selection on breeding values for laying date, estimated from an animal model, indicated that selection acts directly on additive genetic variance underlying breeding time (β = −0.20 ± 0.04), but not on clutch size (β = 0.03 ± 0.05). In contrast, selection on laying date via adult female survival fluctuated in sign between years, and was opposite in sign for selection on phenotypes (negative) and breeding values (positive). Our data thus suggest that any evolutionary response to selection on laying date is partially constrained by underlying life-history trade-offs, and illustrate the difficulties in using purely phenotypic measures and incomplete fitness estimates to assess evolution of life-history trade-offs. We discuss some of the difficulties associated with understanding the evolution of laying date and clutch size in natural populations.