Phylogenetically controlled studies across multiple species correct for taxonomic confounds in physiological performance traits. Therefore, they are preferred over comparisons of two or few closely-related species. Funding bodies, referees and journal editors nowadays often even reject to consider detailed comparisons of two or few closely related species. Here, we plea for a less dogmatic stance on such comparisons, because phylogenetic studies come with their own limitations similar in magnitude as those of two-species comparisons. Two-species comparisons are particularly relevant and instructive for understanding physiological pathways and de novo mutations in three contexts: in a purely mechanistic context, when differences in the regulation of a trait are the focus of investigation, when a physiological trait lacks a direct connection to fitness, and when physiological measures cannot easily be standardized among laboratories. In conclusion, phylogenetic comparative and two-species studies have different strengths and weaknesses and combining these complementary approaches will help integrating biology.

中文翻译：

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系统发育的专制——呼吁对两个物种的比较采取不那么教条的立场

跨多个物种的系统发育控制研究纠正了生理性能特征中的分类混淆。因此，它们优于比较两个或几个密切相关的物种。如今，资助机构、审稿人和期刊编辑甚至经常拒绝考虑对两个或几个密切相关的物种进行详细比较。在这里，我们请求对这种比较采取不那么教条的立场，因为系统发育研究有其自身的局限性，与两个物种的比较相似。两个物种的比较对于理解三种情况下的生理途径和从头突变特别相关和有益：在纯粹的机械背景下，当性状调节的差异是研究的重点时，当生理特征与健康缺乏直接联系，并且生理测量在实验室之间不容易标准化时。总之，系统发育比较研究和两个物种研究具有不同的优势和劣势，结合这些互补的方法将有助于整合生物学。