Caught in the act: anatomy of an ongoing benthic-planktonic transition in a marine protist
Caught in the act: anatomy of an ongoing benthic-planktonic transition in a marine protist
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DOI：
10.1093/plankt/fbx018
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发表时间：
2017-05-01
影响因子：
2.1
通讯作者：
Morard, Raphael
中科院分区：
文献类型：
--
作者：
Kucera, Michal;Silye, Lorand;Morard, Raphael
从底栖生物到浮游生物的转变需要多种适应，但到目前为止，还不清楚这些适应是如何在转变过程中获得的。为了研究这一过程，我们分析了一组具有typtypelagic生活模式的Bolivina属有孔虫的遗传多样性和分布模式（同一物种在底栖动物和浮游生物中都存在）。我们从单细胞DNA提取和远洋环境样本的元条形码中收集了这一群体的全球序列数据集。在玻利维亚，所有的远洋序列都聚集在一个单一的单系分支中。这个分支有三个不同的遗传谱系，这与早期的形态分化有关。所有的谱系都出现在浮游生物和底栖动物中，但只有一个谱系表现出无限制的近海扩散，并已被证明在浮游生物中生长。这些观察结果表明，在进化支系中浮力调节的出现先于远洋捕食的进化，而这两种特征的进化并没有完全过渡到浮游生物。我们推断，在有孔虫中，浮游生态位的定植可能是通过独立获得的特征的顺序交配发生的，而全浮游物种是从食虫祖先那里招募来的。
The transition from benthos to plankton requires multiple adaptations, yet so far it remains unclear how these are acquired in the course of the transition. To investigate this process, we analyzed the genetic diversity and distribution patterns of a group of foraminifera of the genus Bolivina with a tychopelagic mode of life (same species occurring both in benthos and plankton). We assembled a global sequence data set for this group from single-cell DNA extractions and occurrences in metabarcodes from pelagic environmental samples. The pelagic sequences all cluster within a single monophyletic clade within Bolivina. This clade harbors three distinct genetic lineages, which are associated with incipient morphological differentiation. All lineages occur in the plankton and benthos, but only one lineage exhibits no limit to offshore dispersal and has been shown to grow in the plankton. These observations indicate that the emergence of buoyancy regulation within the clade preceded the evolution of pelagic feeding and that the evolution of both traits was not channeled into a full transition into the plankton. We infer that in foraminifera, colonization of the planktonic niche may occur by sequential cooptation of independently acquired traits, with holoplanktonic species being recruited from tychopelagic ancestors.