Department of Zoology and Animal Biology, University of Geneva, Geneva, Switzerland.
PLoS Genet. 2011 Jan 20;7(1):e1001280. doi: 10.1371/journal.pgen.1001280.
The phenotype produced by a given genotype can be strongly modulated by environmental conditions. Therefore, natural populations continuously adapt to environment heterogeneity to maintain optimal phenotypes. It generates a high genetic variation in environment-sensitive gene networks, which is thought to facilitate evolution. Here we analyze the chromatin regulator crm, identified as a candidate for adaptation of Drosophila melanogaster to northern latitudes. We show that crm contributes to environmental canalization. In particular, crm modulates the effect of temperature on a genomic region encoding Hedgehog and Wingless signaling effectors. crm affects this region through both constitutive heterochromatin and Polycomb silencing. Furthermore, we show that crm European and African natural variants shift the reaction norms of plastic traits. Interestingly, traits modulated by crm natural variants can differ markedly between Drosophila species, suggesting that temperature adaptation facilitates their evolution.
给定基因型产生的表型可以被环境条件强烈调节。因此，自然种群不断适应环境异质性以维持最佳表型。这在对环境敏感的基因网络中产生了高度的遗传变异，被认为有助于进化。在这里，我们分析了染色质调节剂 crm，它被认为是黑腹果蝇适应北方纬度的候选基因。我们表明，crm 有助于环境的管道化。特别是，crm 调节温度对编码 Hedgehog 和 Wingless 信号效应物的基因组区域的影响。crm 通过组成型异染色质和 Polycomb 沉默来影响这个区域。此外，我们表明，crm 的欧洲和非洲自然变体改变了可塑特征的反应规范。有趣的是，crm 自然变体调节的特征在不同的果蝇物种之间有明显的差异，这表明温度适应促进了它们的进化。
