Experimental estimation of evolutionary adaptation to cooler climate by Drosophila albomicans during distribution expansion to the temperate zones

摘要本研究以近几十年来从热带向温带迅速扩张的果蝇为研究对象，旨在阐明其适应低温环境的进化分子机制。结果表明，温带品系的耐寒性高于热带品系，冷驯化的影响是一个重要因素。然后，我们发现了在冷驯化过程中表达水平发生很大变化的基因。最后，利用基因操作技术，模拟了黑腹果蝇在冷驯化过程中基因表达的变化，揭示了部分基因表达水平的变化与耐寒性的提高有关。

This study was aimed at clarifying molecular mechanisms of evolutionary adaptation to low temperature environment, using a fruit fly species (Drosophila albomicans) which has rapidly expanded their geographic distribution from the tropics to temperate zones during a recent few decades. It was shown that a cold tolerance of temperate zone strains was higher than that of tropical strains and that the effect of cold acclimation was an important factor. We then found the genes whose expression level was largely changed during the cold acclimation. Finally, using gene manipulation techniques in Drosophila melanogaster, we simulated the gene expression changes observed during the cold acclimation in Drosophila albomicans and showed that the changes in expression level of some of the genes were responsible for the improvement of cold tolerance.