Center for Applied Mathematics, UMR 7641 CNRS, Ecole Polytechnique, 91128 Palaiseau, France.
Evolution. 2012 Aug;66(8):2577-86. doi: 10.1111/j.1558-5646.2012.01598.x. Epub 2012 Mar 12.
The current diversity of life on earth is the product of macroevolutionary processes that have shaped the dynamics of diversification. Although the tempo of diversification has been studied extensively in macroorganisms, much less is known about the rates of diversification in the exceedingly diverse and species-rich microbiota. Decreases in diversification rates over time, a signature of explosive radiations, are commonly observed in plant and animal lineages. However, the few existing analyses of microbial lineages suggest that the tempo of diversification in prokaryotes may be fundamentally different. Here, we use multilocus and genomic sequence data to test hypotheses about the rate of diversification in a well-studied pathogenic bacterial lineage, Borrelia burgdorferi sensu lato (sl). Our analyses support the hypothesis that an explosive radiation of lineages occurred near the origin of the clade, followed by a sharp decay in diversification rates. These results suggest that explosive radiations may be a general feature of evolutionary history across the tree of life.
目前地球上生命的多样性是塑造多样化动态的宏观进化过程的产物。尽管宏观生物中广泛研究了多样化的节奏，但对于极其多样化和物种丰富的微生物群的多样化速度知之甚少。随着时间的推移，多样化率的下降是植物和动物谱系中爆发辐射的标志。然而，对微生物谱系的少数现有分析表明，原核生物多样化的节奏可能从根本上不同。在这里，我们使用多位点和基因组序列数据来检验关于研究得很好的致病性细菌谱系 Borrelia burgdorferi sensu lato (sl) 多样化率的假设。我们的分析支持这样的假设，即在进化枝的起源附近发生了谱系的爆发性辐射，随后多样化率急剧下降。这些结果表明，爆发性辐射可能是整个生命之树进化历史的普遍特征。
