Gibert Patricia, Moreteau Brigitte, Moreteau Jean-Claude, David Jean R
CNRS, Laboratoire Populations, Génétique et Evolution, 91198-Gif sur Yvette Cedex, France.
Université de Metz, Laboratoire de Démoécologie 1, rue des Récollets 57000 Metz Cedex, France.
Evolution. 1996 Dec;50(6):2346-2353. doi: 10.1111/j.1558-5646.1996.tb03622.x.
Phenotypic plasticity of abdomen pigmentation was investigated in populations of the sibling species Drosophila melanogaster and D. simulans, living in sympatry in two French localities. Ten isofemale lines of each population and species were grown at different constant temperatures spanning their complete thermal range from 12 to 31°C. Genetic variability between isofemale lines was not affected by growth temperature, but was consistently less in D. simulans. For all traits, the dark pigmentation of the abdominal segments decreased according to growth temperature, in agreement with the thermal budget adaptive hypothesis. The shapes of the response curves were different between the abdominal segments, but for a given segment, quite similar in the two species. On average D. simulans was lighter than D. melanogaster, but the difference was mainly expressed at higher temperatures. An interesting result was the difference observed between the two localities: flies from the colder locality (Villeurbanne) were found to be darker than flies from the warmer locality (Bordeaux). Interestingly, this difference was expressed only at low temperatures, 21°C and below, that is, at temperatures encountered in natural conditions. This suggests an adaptive response resulting in a change of the shape of reaction norm and involving genotype-environment interactions. When comparing the genetic structure of geographic populations for quantitative traits, several laboratory environments should be preferred to a single one.
在法国两个地区同域分布的黑腹果蝇和拟果蝇这两个姐妹物种的种群中，研究了腹部色素沉着的表型可塑性。每个种群和物种的10个同雌系在12至31°C的完整热范围内的不同恒定温度下培养。同雌系之间的遗传变异性不受生长温度的影响，但在拟果蝇中始终较低。对于所有性状，腹部节段的深色色素沉着根据生长温度而降低，这与热预算适应性假说一致。腹部节段之间的反应曲线形状不同，但对于给定的节段，两个物种非常相似。平均而言，拟果蝇比黑腹果蝇颜色浅，但差异主要在较高温度下表现出来。一个有趣的结果是在两个地区之间观察到的差异：发现来自较冷地区（维勒班）的果蝇比来自较温暖地区（波尔多）的果蝇颜色更深。有趣的是，这种差异仅在低温（21°C及以下）时表现出来，即在自然条件下遇到的温度下。这表明一种适应性反应导致反应规范形状的改变，并涉及基因型-环境相互作用。在比较地理种群数量性状的遗传结构时，几个实验室环境应优于单一环境。
