Abstract Understanding how and why rates of character evolution vary across the Tree of Life is central to many evolutionary questions; for example, does the trophic apparatus (a set of continuous characters) evolve at a higher rate in fish lineages that dwell in reef versus nonreef habitats (a discrete character)? Existing approaches for inferring the relationship between a discrete character and rates of continuous-character evolution rely on comparing a null model (in which rates of continuous-character evolution are constant across lineages) to an alternative model (in which rates of continuous-character evolution depend on the state of the discrete character under consideration). However, these approaches are susceptible to a “straw-man” effect: the influence of the discrete character is inflated because the null model is extremely unrealistic. Here, we describe MuSSCRat, a Bayesian approach for inferring the impact of a discrete trait on rates of continuous-character evolution in the presence of alternative sources of rate variation (“background-rate variation”). We demonstrate by simulation that our method is able to reliably infer the degree of state-dependent rate variation, and show that ignoring background-rate variation leads to biased inferences regarding the degree of state-dependent rate variation in grunts (the fish group Haemulidae). [Bayesian phylogenetic comparative methods; continuous-character evolution; data augmentation; discrete-character evolution.]

中文翻译：

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一种贝叶斯方法，用于在存在背景速率变化的情况下推断离散字符对连续字符演化速率的影响

摘要 了解生命之树中性格进化速度如何以及为何不同是许多进化问题的核心。例如，与非珊瑚礁栖息地相比，栖息在珊瑚礁栖息地的鱼类谱系（离散特征）中的营养器官（一组连续特征）是否以更高的速度进化？推断离散字符与连续字符进化速率之间关系的现有方法依赖于将空模型（其中连续字符进化速率跨谱系恒定）与替代模型（其中连续字符进化速率取决于所考虑的离散字符的状态）。然而，这些方法容易受到“稻草人”效应的影响：离散特征的影响被夸大了，因为空模型非常不切实际。在这里，我们描述了 MuSSCRat，这是一种贝叶斯方法，用于在存在速率变异的替代来源（“背景速率变异”）的情况下推断离散特征对连续字符进化速率的影响。我们通过模拟证明我们的方法能够可靠地推断状态依赖率变化的程度，并表明忽略背景率变化会导致对咕噜声（鱼群 Haemulidae）状态依赖率变化程度的有偏见的推断. [贝叶斯系统发育比较方法；连续字符进化；数据增强；离散字符进化。] 一种贝叶斯方法，用于在存在速率变异的替代来源（“背景速率变异”）的情况下推断离散特征对连续字符进化速率的影响。我们通过模拟证明我们的方法能够可靠地推断状态依赖率变化的程度，并表明忽略背景率变化会导致对咕噜声（鱼群 Haemulidae）状态依赖率变化程度的有偏见的推断. [贝叶斯系统发育比较方法；连续字符进化；数据增强；离散字符进化。] 一种贝叶斯方法，用于在存在速率变异的替代来源（“背景速率变异”）的情况下推断离散特征对连续字符进化速率的影响。我们通过模拟证明我们的方法能够可靠地推断状态依赖率变化的程度，并表明忽略背景率变化会导致对咕噜声（鱼群 Haemulidae）状态依赖率变化程度的有偏见的推断. [贝叶斯系统发育比较方法；连续字符进化；数据增强；离散字符进化。] 并表明忽略背景速率变化会导致对咕噜声（鱼群 Haemulidae）的状态依赖速率变化程度的有偏见的推断。[贝叶斯系统发育比较方法；连续字符进化；数据增强；离散字符进化。] 并表明忽略背景速率变化会导致对咕噜声（鱼群 Haemulidae）的状态依赖速率变化程度的有偏见的推断。[贝叶斯系统发育比较方法；连续字符进化；数据增强；离散字符进化。]