Stayton C Tristan
Department of Biology , Bucknell University , Lewisburg, PA 17837 , USA.
Interface Focus. 2015 Dec 6;5(6):20150039. doi: 10.1098/rsfs.2015.0039.
Convergent evolution is central to the study of life's evolutionary history. Researchers have documented the ubiquity of convergence and have used this ubiquity to make inferences about the nature of limits on evolution. However, these inferences are compromised by unrecognized inconsistencies in the definitions, measures, significance tests and inferred causes of convergent evolution. I review these inconsistencies and provide recommendations for standardizing studies of convergence. A fundamental dichotomy exists between definitions that describe convergence as a pattern and those that describe it as a pattern caused by a particular process. When this distinction is not acknowledged it becomes easy to assume that a pattern of convergence indicates that a particular process has been active, leading researchers away from alternative explanations. Convergence is not necessarily caused by limits to evolution, either adaptation or constraint; even substantial amounts of convergent evolution can be generated by a purely stochastic process. In the absence of null models, long lists of examples of convergent events do not necessarily indicate that convergence or any evolutionary process is ubiquitous throughout the history of life. Pattern-based definitions of convergence, coupled with quantitative measures and null models, must be applied before drawing inferences regarding large-scale limits to evolution.
趋同进化是生命进化史研究的核心。研究人员已经记录了趋同现象的普遍性，并利用这种普遍性对进化的限制本质进行推断。然而，这些推断受到趋同进化的定义、衡量标准、显著性检验及推断原因中未被认识到的不一致性的影响。我回顾了这些不一致性，并为趋同研究的标准化提供建议。在将趋同描述为一种模式的定义和将其描述为由特定过程导致的模式的定义之间，存在着根本的二分法。当这种区别未被认同时，就很容易假定趋同模式表明某个特定过程是活跃的，从而使研究人员偏离其他解释。趋同不一定是由进化的限制（适应或约束）所导致；即使是大量的趋同进化也可能由纯粹的随机过程产生。在没有零模型的情况下，一长串趋同事件的例子并不一定表明趋同或任何进化过程在生命史上是普遍存在的。在对大规模进化限制进行推断之前，必须应用基于模式的趋同定义，并结合定量测量和零模型。
