Olsson Mats, Gullberg Annica, Shine Richard, Madsen Thomas, Tegelström Håkan
University of Göteborg, Department of Zoology, Section of Animal Ecology, Medicinaregatan 18, S-413 90, Göteborg, Sweden.
The University of Sydney, School of Biological Sciences, Zoology Building A08, N.S.W. 2006, Australia.
Evolution. 1996 Jun;50(3):1328-1333. doi: 10.1111/j.1558-5646.1996.tb02372.x.
Theoretical models for the evolution of life-history traits assume a genetic basis for a significant proportion of the phenotypic variance observed in characteristics such as hatching date and offspring size. However, recent experimental work has shown that much of the phenotypic variance in hatchling reptiles is induced by nongenetic factors, such as maternal nutrition and thermoregulation, and the physical conditions experienced during embryogenesis. Thus, there is no unambiguous evidence for strictly genetic (intraspecific) influences on the phenotypes of hatchling reptiles. We report results from a technique that uses a genetic marker trait and DNA fingerprinting to determine paternity of offspring from multiply sired clutches of European sand lizards, Lacerta agilis. By focusing on paternal rather than maternal effects, we show that hatchling genotypes exert a direct influence on the duration of incubation, the size (mass, snout-vent length) and shape (relative tail length) of the hatchling, and subsequent growth rates of the lizard during the first 3 mo of life. Embryos with genes that code for a few days' delay in hatching are thereby larger when they hatch, having undergone further differentiation (and hence, have changed in bodily proportions), and are able to grow faster after hatching. Our data thus provide empirical support for a crucial but rarely tested assumption of life-history theory, and illuminate some of the proximate mechanisms that produce intraspecific variation in offspring phenotypes.
生活史特征进化的理论模型假定，在诸如孵化日期和后代大小等特征中观察到的很大一部分表型变异具有遗传基础。然而，最近的实验工作表明，孵化期爬行动物的许多表型变异是由非遗传因素引起的，如母体营养和体温调节，以及胚胎发育过程中所经历的物理条件。因此，没有明确的证据表明严格的遗传（种内）因素会影响孵化期爬行动物的表型。我们报告了一项技术的结果，该技术使用遗传标记性状和DNA指纹识别来确定欧洲沙蜥（Lacerta agilis）多父系窝中后代的父系。通过关注父系而非母系效应，我们表明孵化期基因型对孵化持续时间、孵化期幼体的大小（体重、吻肛长度）和形状（相对尾长）以及蜥蜴出生后前3个月的生长速度有直接影响。携带编码孵化延迟几天基因的胚胎孵化时体型更大，已经历了进一步分化（因此身体比例发生了变化），并且孵化后能够生长得更快。因此，我们的数据为生活史理论中一个关键但很少被检验的假设提供了实证支持，并阐明了一些导致后代表型种内变异的近端机制。
