Genetic architecture of thermal adaptation in Escherichia coli.
Genetic architecture of thermal adaptation in Escherichia coli.
复制标题
大肠杆菌热适应的遗传结构。
DOI：
10.1073/pnas.98.2.525
复制
发表时间：
2001
影响因子：
11.1
通讯作者：
Long,AD
中科院分区：
文献类型：
--
作者：
Riehle,MM;Bennett,AF;Long,AD
在全基因组范围内阐明适应的遗传基础一直是生物学家们所回避的问题，但完整的基因组序列和DNA高密度阵列技术使全基因组调查变得更加容易。 利用DNA高密度阵列技术，对6株在41.5°C高温胁迫下适应了2,000代的大肠杆菌进行了全基因组范围内的重复/缺失事件检测。共检测到5个重复和缺失事件。这五个事件发生在六条线路中的三条线路中，而其余三条线路不包含可检测的事件。其中3个重复的电子束为2.85Mb。colichromosome，提供了证据的复制适应高温。四个候选基因先前显示在压力和饥饿生存中发挥作用，确定在该地区的共同重复。检测的两个候选基因的表达相对于祖先系或没有重复的系中的表达水平升高。在2.85 Mb处的重复已被进一步表征的两种情况下，基因组重组的时间与相对适合度的显著增加一致。在这两种情况下，复制起源的模型是涉及插入序列和重复序列的复杂重组事件。这些结果为基因复制在适应中起着不可或缺的作用，特别是作为基因扩增的一种手段提供了额外的证据。
Elucidating the genetic basis of adaptation on a genomewide scale has evaded biologists, but complete genome sequences and DNA high-density array technology make genomewide surveys more tractable. Six lines ofEscherichia coliadapted for 2,000 generations to a stressful high temperature of 41.5°C were examined on a genomewide scale for duplication/deletion events by using DNA high-density arrays. A total of five duplication and deletion events were detected. These five events occurred in three of the six lines, whereas the remaining three lines contained no detectable events. Three of the duplications were at 2.85 Mb of theE. colichromosome, providing evidence for the replicability of the adaptation to high temperature. Four candidate genes previously shown to play roles in stress and starvation survival were identified in the region of common duplication. Expression of the two candidate genes examined is elevated over expression levels in the ancestral lines or the lines without the duplication. In the two cases where the duplication at 2.85 Mb has been further characterized, the timing of the genome reorganization is coincident with significant increases in relative fitness. In both of these cases, the model for the origin of the duplication is a complex recombination event involving insertion sequences and repeat sequences. These results provide additional evidence for the idea that gene duplication plays an integral role in adaptation, specifically as a means for gene amplification.