Experimental evolution of Hsp70 expression and thermotolerance in Drosophila melanogaster.
Experimental evolution of Hsp70 expression and thermotolerance in Drosophila melanogaster.
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DOI：
10.2307/2640784
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发表时间：
1999-04-01
期刊：
影响因子：
3.3
通讯作者：
Cavicchi, S
中科院分区：
文献类型：
--
作者：
Bettencourt, BR;Feder, ME;Cavicchi, S
为了检查最近的进化历史是否影响果蝇中主要的热诱导热休克蛋白 Hsp70 的表达，我们测量了在不同温度下进行实验室进化的复制群体中的 Hsp70 表达、耐热性和 hsp70 基因数量。尽管 Hsp70 具有古老且高度保守的性质，但实验进化有效且可复制地改变了其表达和表型（耐热性）。在由共同祖先群体建立的五个 D、黑腹果蝇群体中，在 18°C 的三种不同温度下饲养，在 25°C 和 28°C 各两个温度下饲养二十年，Hsp70 表达以一致的模式变化：在一系列诱导温度下，重复的 28°C 品系表达的 Hsp70 比其他品系少 30-50%。这种修饰难以适应环境，并且与耐热性相关：28°C 品系在 38.5°C 和 39°C 的诱导耐受性显着降低。我们验证了每个品系的基因组中存在 5 个 hsp70 基因，排除了作为表达进化差异的候选分子基础的拷贝数变异。这些发现支持黑腹果蝇群体中 Hsp70 水平在微进化时间尺度上发生变化的能力，并表明环境温度的恒定性是一种潜在的重要选择剂。
To examine whether recent evolutionary history affects the expression of Hsp70, the major heat-induced-heat shock protein in Drosophila melanogaster, we measured Hsp70 expression, thermotolerance, and hsp70 gene number in replicate populations undergoing laboratory evolution at different temperatures. Despite Hsp70's ancient and highly conserved nature, experimental evolution effectively and replicably modified its expression and phenotype (thermotolerance). Among five D, melanogaster populations founded from a common ancestral population and raised at three different temperatures tone at 18 degrees C, two each at 25 degrees C and 28 degrees C for twenty years, Hsp70 expression varies in a consistent pattern: the replicate 28 degrees C lines expressed 30-50% less Hsp70 than the other Lines at a range of inducing temperatures. This modification was refractory to acclimation, and correlated with thermotolerance: the 28 degrees C lines had significantly lower inducible tolerance of 38.5 degrees C and 39 degrees C. We verified the presence of five hsp70 genes in the genome of each line, excluding copy number variation as a candidate molecular basis of the evolved difference in expression. These findings support the ability of Hsp70 levels in D. melanogaster populations to change over microevolutionary time scales and implicate constancy of environmental temperature as a potentially important selective agent.