ABSTRACT: Relationships between animals and their associated microbiota are dependent on both the evolutionary history of the host and on the environment. The majority of studies tend to focus on either one of these factors but rarely consider how both determine the community composition of the associated microbiota. One ‘natural experiment’ to test how evolutionary history, shared environments, and the interaction between these factors drive community composition is to compare geminate species pairs. Echinoids separated by the Isthmus of Panama are suitable for this comparison due to their known evolutionary history and differences in the oceanographic characteristics of the Caribbean Sea and the Pacific Ocean. By comparing the bacterial communities of the eggs of Echinometra and Diadema geminate species pairs, we show that each pair of geminate species associates with a distinct bacterial community in a pattern consistent with phylosymbiosis, and that the interaction between the evolutionary history of the host and the environment best explains differences in these communities. Moreover, we found that the relative abundance of particular bacterial taxa differed considerably between the 2 bodies of water and that the 2 Caribbean Echinometra species were dominated by unclassified bacterial taxa within the phototrophic Oxyphotobacteria. Taken together, data presented here support the hypothesis that the bacterial communities associated with geminate species are another characteristic of these species that have diverged in ~2.8 million years of isolation.

中文翻译：

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巴拿马地峡分离的类固醇卵含有不同的菌群

摘要：动物及其相关微生物群之间的关系既取决于宿主的进化史，也取决于环境。大多数研究倾向于集中于这些因素之一，但很少考虑两者如何决定相关微生物群的群落组成。测试进化史，共享环境以及这些因素之间的相互作用如何驱动群落组成的一项“自然实验”是比较成对物种。由巴拿马地峡分隔的类固醇因其已知的进化史以及加勒比海和太平洋海洋学特征的差异而适合进行此比较。通过比较卵的细菌群落Echinometra和迪亚德马配对物种，我们显示每对配对物种均以与共生共生的模式与不同的细菌群落相关联，并且宿主进化史与环境之间的相互作用可以最好地解释这些群落之间的差异。此外，我们发现特定细菌类群的相对丰度在2个水体之间存在显着差异，并且2个加勒比海棘皮动物物种在光养性Oxyphotobacteria中以未分类的细菌类群为主。综上所述，这里提供的数据支持以下假设：与发芽物种相关的细菌群落是这些物种的另一个特征，这些物种在约280万年的隔离中有所不同。