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首页> 外文期刊>Journal of genetics >Are bigger flies always better: the role of genes and environment
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Are bigger flies always better: the role of genes and environment

机译：苍蝇总是更好：基因和环境的作用

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Body size, especially in invertebrates, is often positively correlated with major fitness components such as female fecundity and male mating success, and it is believed that the evolution of larval growth rate and adult body size in insects is largely shaped by a tradeoff between the fitness benefits of being large versus those of developing to adulthood fast (Santos et al. 1988; Partridge and Fowler 1993). Understanding the phenotypic inter-relationships between development time, body size and adult fitness components in insects, and how these relationships are affected by genotype and environment, is therefore directly relevant to two contentious and central issues in evolutionary genetics: (1) the nature of genetic constraints on the attainment of an optimal life-history, and (2) the relative role of geno-typic and environmental variation and covariation in determining the magnitude and sign of phenotypic correlations between fitness related traits (Prasad and Joshi 2003). Almost half a century ago, in a characteristically rigorous and detailed study, Robertson (1957) examined the nature of genetic variation and covariation between body size (thorax length) and egg production (total fecundity between days 4-8 post-eclosion), under benign and uniform rearing conditions, in a large, genetically variable laboratory population of Drosophila melanogaster. The major findings of Robertson's (1957) study were that (a) there was a significant positive phenotypic correlation between body size and egg production, (b) about 50% of the phenotypic variance in body size was due to genetic variation, mostly additive, (c) about 60% of the phenotypic variance in egg production was due to genetic variation, with a large non-additive component, (d) body size and egg production appeared to be independently genetically correlated with development time, the latter negatively and the former positively, and (e) the genetic correlation underlying the positive phenotypic correlation between body size and egg production was largely non-additive.
机译：体型，尤其是无脊椎动物的体型，通常与主要的适应性成分（如雌性繁殖力和雄性交配成功率）呈正相关，并且据信，昆虫中幼虫的生长速度和成年体型的演变很大程度上取决于适应性之间的权衡相对于快速成长到成年的好处（Santos等，1988; Partridge和Fowler，1993）。因此，了解昆虫的发育时间，体型和成年适应性成分之间的表型相互关系，以及这些关系如何受到基因型和环境的影响，直接关系到进化遗传学中两个有争议的核心问题：（1）昆虫的本质遗传因素对获得最佳生活史的影响;以及（2）基因型与环境变异和协变在确定健身相关性状之间的表型相关性的大小和符号方面的相对作用（Prasad and Joshi 2003）。大约半个世纪前，Robertson（1957）在一项特征严谨而详尽的研究中，研究了个体大小（胸部长度）与产卵量（出卵后4-8天之间的总生殖力）之间的遗传变异和协变的性质。在大量有遗传变异的果蝇果蝇实验室中，饲养条件良好且均匀。 Robertson（1957）研究的主要发现是（a）体重与产蛋量之间存在显着的正表型相关性;（b）体重表型变异中约有50％是由于遗传变异，主要是累加的， （c）大约60％的产蛋表型变异是由于遗传变异造成的，具有较大的非累加成分，（d）体重和产蛋量似乎与发育时间具有独立的遗传相关性，而后者与生长时间呈负相关。 （e）个体大小和产蛋量之间呈正表型相关的遗传相关性在很大程度上没有累加性。

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