Travis Joseph, Emerson Sharon B, Blouin Michael
Department of Biological Science, Florida State University, Tallahassee, FL, 32306-2043.
Division of Amphibians and Reptiles, Field Museum of Natural History, Chicago, IL, 60605-2496.
Evolution. 1987 Jan;41(1):145-156. doi: 10.1111/j.1558-5646.1987.tb05777.x.
We used a half-sib design to examine the genetic components of phenotypic variance in several life-history traits in Hyla crucifer. Egg viability, hatchling size, larval growth rate, length of larval period, and size at metamorphosis play critical roles in determining survivorship and are subject to persistent selection. Egg viability varied among families considerably, with most embryo mortality occurring between gastrulation and neurulation. Hatchling size was the only trait in which maternal effects were influential. Dominance genetic variance played the predominant role in determining phenotypic variance in hatchling size, growth rate, and length of larval period, accounting for, respectively, 70, 63, and 47% of the total variance. Size at metamorphosis displayed little dominance genetic variance and, unlike the other traits, displayed a high heritability. All additive genetic correlations between traits were positive. The directions of environmental correlations were the same as the directions of changes that have been induced in previous experimental work. The correlations due to dominance effects described a principal axis that independent ecological studies indicate to be directly correlated with fitness. These results agree with theoretical expectations for traits under consistent directional selection.
我们采用半同胞设计来研究雨蛙（Hyla crucifer）若干生活史性状表型变异的遗传成分。卵的活力、幼体大小、幼体生长速率、幼体期长度以及变态时的大小在决定存活率方面起着关键作用，并且受到持续的选择作用。卵的活力在不同家系间差异很大，大多数胚胎死亡发生在原肠胚形成和神经胚形成之间。幼体大小是唯一受母体效应影响的性状。显性遗传方差在决定幼体大小、生长速率和幼体期长度的表型方差中起主要作用，分别占总方差的70%、63%和47%。变态时的大小显示出很少的显性遗传方差，并且与其他性状不同，表现出高遗传力。性状之间所有的加性遗传相关性均为正。环境相关性的方向与先前实验工作中诱导的变化方向相同。由显性效应引起的相关性描述了一个主轴，独立的生态学研究表明该主轴与适合度直接相关。这些结果与在一致的定向选择下性状的理论预期相符。
