Data from: Selection at the Esterase-2 locus of Drosophila buzzatii? Perturbation-reperturbation experiments

Apparent selection affecting starch gel electrophoretic alleles at the Esterase-2 locus of Drosophila buzzatii has been detected in laboratory and natural populations. Perturbation-reperturbation of allele frequencies in replicated laboratory populations attempts to test direct selective effects at the locus versus effects of linked loci. Sequential gel electrophoresis has identified more alleles within starch classes, and three of these alleles (within the a, b and c starch alleles) were used in cage population experiments. Allele a/1.00/1.00/1.00 was set up in 10 replicate populations with allele c/1.00/1.00/1.00, and in an independent 10 replicate populations with allele b/0.99/1.01/1.00. For each set, three reperturbations were done. Replicate populations generally showed similar patterns of allele frequency change and clear directionality: effects of selection, not drift. However, four populations deviated from their replicates, indicating dissipation of linkage disequilibrium. Estimates of pre-adult viability in the F2 of pair-wise crosses among 12 sequential gel electrophoretic alleles showed very variable modes of inheritance and relative viability fitnesses. Together with the diversity of patterns of allele frequency change in the cage populations, these results suggest a gene complex, with selection acting on an interacting set of loci which may include Esterase-2.

本研究在实验室种群与自然种群中，均检测到巴滋果蝇（Drosophila buzzatii）酯酶-2（Esterase-2）位点处淀粉凝胶电泳（starch gel electrophoresis）等位基因受到表观选择作用的效应。通过对重复实验室种群的等位基因频率进行扰动-再扰动处理，旨在区分该位点的直接选择效应与连锁位点所介导的效应。通过顺序凝胶电泳技术，在淀粉迁移类群中鉴定出更多等位基因，其中a、b、c三类淀粉迁移等位基因所包含的3个等位基因被用于笼养种群实验。以等位基因a/1.00/1.00/1.00与等位基因c/1.00/1.00/1.00为组合，构建10个重复种群；同时另设独立的10个重复种群，以等位基因a/1.00/1.00/1.00与等位基因b/0.99/1.01/1.00为组合。每个实验组均进行3次扰动-再扰动处理。重复种群通常呈现出相似的等位基因频率变化模式与清晰的方向性，这表明该效应由选择而非遗传漂变所导致。然而有4个种群偏离了其所在重复组的整体趋势，这提示连锁不平衡（linkage disequilibrium）发生了消散。对12个经顺序凝胶电泳鉴定的等位基因之间的两两杂交F2代的成虫前期存活率进行估算，结果显示其遗传模式与相对存活适合度均存在极高的变异性。结合笼养种群中等位基因频率变化模式的多样性，上述结果表明存在一个基因复合体，选择作用于一组相互作用的位点，其中可能包含酯酶-2（Esterase-2）位点。