Rates of molecular evolution in bacteria are relatively constant despite spore dormancy
Rates of molecular evolution in bacteria are relatively constant despite spore dormancy
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DOI：
10.1111/j.1558-5646.2007.00026.x
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发表时间：
2007-02-01
期刊：
影响因子：
3.3
通讯作者：
Maughan, Heather
中科院分区：
文献类型：
--
作者：
Maughan, Heather
已知分子进化的速率在不同谱系之间有很大的差异，部分原因是生活史特征的差异，如世代时间。世代-时间效应在一些真核生物中已经有很好的记录，但其在原核生物中的普遍性尚不清楚。“由于许多种类的厚壁菌作为代谢休眠孢子花费了很长时间，这可能导致单位时间内DNA替换较少，因此它们为测试分子钟假设的预测提供了一个很好的系统。“为了测试孢子形成细菌是否比它们的非孢子形成亲戚进化得更慢，我使用系统发育方法来确定厚壁菌属孢子形成和非孢子形成谱系之间的氨基酸取代率是否存在差异。虽然进化的速度各不相同的血统，我发现没有证据的孢子形成的进化速度的影响，此外，进化速度是类似的计算肠道细菌。这些结果支持了世代时间的变化不影响细菌谱系进化速率的观点。
Rates of molecular evolution are known to vary considerably among lineages, partially due to differences in life-history traits such as generation time. The generation-time effect has been well documented in some eukaryotes, but its prevalence in prokaryotes is unknown. "Because many species of Firmicute bacteria spend long periods of time as metabolically dormant spores, which could result in fewer DNA substitutions per unit time, they present an excellent system for testing predictions of the molecular clock hypothesis." To test whether spore-forming bacteria evolve more slowly than their non-spore-forming relatives, I used phylogenetic methods to determine if there were differences in rates of amino acid substitution between spore-forming and non-spore-forming lineages of Firmicute bacteria. Although rates of evolution do vary among lineages, I find no evidence for an effect of spore-formation on evolutionary rate and, furthermore, evolutionary rates are similar to those calculated for enteric bacteria. These results support the notion that variation in generation time does not affect evolutionary rates in bacterial lineages.