Inclusion of a near-complete fossil record reveals speciation-related molecular evolution
Inclusion of a near-complete fossil record reveals speciation-related molecular evolution
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DOI：
10.1111/2041-210x.12089
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发表时间：
2013-08-01
影响因子：
6.6
通讯作者：
Purvis, Andy
中科院分区：
文献类型：
--
作者：
Ezard, Thomas H. G.;Thomas, Gavin H.;Purvis, Andy
1.遗传进化的速率在谱系之间往往变化太大，以至于不能用严格的分子钟来解释，促使替代生态学和进化假说来解释这种速率异质性。一个有争议的假设是，物种形成引发了一系列快速的遗传变化，使分子进化具有了间断性的成分。因此，根到根尖的遗传变化量往往随着分子生物学中沿根到根尖路径沿着鉴定的物种形成事件（节点）的数量而增加。争议的产生是因为分子遗传上的节点通常只能在两个后代都是外显的情况下才能被计数。在这里，我们使用地层学、系统发育学和生态学数据，从新生代大型浮游有孔虫的特殊化石记录中，根据化石谱系、化石形态种和分子种的概念，检验是否可以用生态因素（丰度、生活史和环境）和物种形成事件的数量来解释谱系速率的不均匀性.在化石谱系的根-尖进化过程中，根-尖之间的节点数与同一根-尖路径上的分子进化速率具有统计学显著相关性，而来自其他物种概念和假设的生态驱动因素的物种形成计数则支持得相对较少.我们的研究结果展示了化石记录如何包含驱动遗传进化的生物过程的信号，证明了在研究地质时间尺度上的宏观进化时进一步结合化石和分子数据的必要性。
1. The rate of genetic evolution is often too variable among lineages to be explained by a strict molecular clock, prompting alternative ecological and evolutionary hypotheses to explain this rate heterogeneity.2. One controversial hypothesis is that speciation provokes a burst of rapid genetic change, giving molecular evolution a punctuational component. The amount of root-to-tip genetic change therefore tends to increase with the number of identified speciation events (nodes) along the root-to-tip path in molecular phylogenies. The controversy arises because nodes on molecular phylogenies can typically only be counted if both descendants are extant.3. Here, using stratigraphic, phylogenetic and ecological data from the exceptional fossil record of Cenozoic macroperforate planktonic foraminifera, we test whether among-lineage rate heterogeneity is explained by ecological factors (abundance, life history and environment) and by the numbers of speciation events according to fossil lineage, fossil morphospecies and molecular species concepts.4. The number of nodes between root and tips on the fossil lineage phylogeny was a statistically significant correlate of the rate of molecular evolution over the same root-to-tip path. The speciation counts from other species concepts and hypothesized ecological drivers had considerably less support.5. Our results showcase how the fossil record contains signals of biological processes that drive genetic evolution, justifying calls to further marry fossil and molecular data when studying macroevolution over geological time-scales.