Fanara J J, Folguera G, Iriarte P F, Mensch J, Hasson E
Laboratorio de Evolución, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria Pab. II, (1428) Buenos Aires, Argentina.
J Evol Biol. 2006 May;19(3):900-8. doi: 10.1111/j.1420-9101.2006.01084.x.
The genetic and ecological basis of viability and developmental time differences between Drosophila buzzatii and D. koepferae were analysed using the isofemale line technique. Several isofemale lines were sampled from pairs of allopatric/sympatric populations of each species. Flies were reared in media prepared with decaying tissues of two of the main natural cactus hosts of each species. This experimental design enabled us to evaluate the relative contribution of phenotypic plasticity, genetic variation and genotype by environment interaction (G x E) to total phenotypic variation for two fitness traits, viability and developmental time. Our results revealed significant G x E in both traits, suggesting that the maintenance of genetic variation can be explained, at least in part, by diversifying selection in different patches of a heterogeneous environment in both species. However, the relative importance of the factors involved in the G x E varied between traits and populations within species. For viability, the G x E can be mainly attributed to changes in the rank order of lines across cacti. However, the pattern was different for developmental time. In D. buzzatii the G x E can be mainly accounted for by changes in among line variance across cacti, whereas changes in the rank order of lines across cacti was the main component in D. koepferae. These dissimilar patterns of variation between traits and species suggest that the evolutionary forces shaping genetic variation for developmental time and viability vary between populations within species and between species.
利用同雌系技术分析了巴氏果蝇（Drosophila buzzatii）和科普费尔果蝇（D. koepferae）之间生存力和发育时间差异的遗传和生态基础。从每个物种的异地/同域种群对中抽取了几个同雌系。果蝇在以每个物种的两种主要天然仙人掌宿主的腐烂组织制备的培养基中饲养。这种实验设计使我们能够评估表型可塑性、遗传变异以及基因型与环境互作（G×E）对生存力和发育时间这两个适合度性状总表型变异的相对贡献。我们的结果显示，这两个性状均存在显著的G×E，表明遗传变异的维持至少部分可以通过两个物种在异质环境不同斑块中的多样化选择来解释。然而，参与G×E的因素的相对重要性在性状和物种内的种群之间有所不同。对于生存力，G×E主要可归因于不同仙人掌上线系排名顺序的变化。然而，发育时间的模式则不同。在巴氏果蝇中，G×E主要可由不同仙人掌上线系间方差的变化来解释，而在科普费尔果蝇中，不同仙人掌上线系排名顺序的变化是主要组成部分。性状和物种之间这些不同的变异模式表明，塑造发育时间和生存力遗传变异的进化力量在物种内的种群之间以及物种之间存在差异。
