Adaptive divergence across Southern Ocean gradients in the pelagic diatom Fragilariopsis kerguelensis
Adaptive divergence across Southern Ocean gradients in the pelagic diatom Fragilariopsis kerguelensis
复制标题
DOI：
10.1111/mec.15554
复制
发表时间：
2020-07
影响因子：
4.9
通讯作者：
U. Postel;Barbara Glemser;Katherine Salazar Alekseyeva;S. L. Eggers;Marco Groth;G. Glöckner;U. John;T. Mock;K. Klemm;K. Valentin;B. Beszteri
中科院分区：
文献类型：
--
作者：
U. Postel;Barbara Glemser;Katherine Salazar Alekseyeva;S. L. Eggers;Marco Groth;G. Glöckner;U. John;T. Mock;K. Klemm;K. Valentin;B. Beszteri
南大洋的特点是纵向水循环被强烈的纬度梯度交叉。尽管该地区对全球生物地球化学循环具有重要意义，但海洋背景如何塑造浮游生物种群在很大程度上是未知的。本文基于基因组学、形态计量学、生态生理学和交配相容性数据，展示了一种特有的远洋生物——脆弱硅藻（Fragilariopsis kerguelensis）的生态型分化和物种形成。我们发现了三种基因型变异，一种存在于整个纬度样带样本中，另一种分别局限于北方和南方。后两者在所有三个基因组中表现出互惠的单系性和显著的生态生理差异，与局部适应一致，但在实验室杂交中产生了可存活的后代。第三组也与后两组进行了生殖分离。我们假设这种模式起源于伴随生态型分化的适应性扩张，随后是同域物种形成。
The Southern Ocean is characterized by longitudinal water circulations crossed by strong latitudinal gradients. How this oceanographic background shapes planktonic populations is largely unknown, despite the significance of this region for global biogeochemical cycles. Here, we show, based on genomic, morphometric, ecophysiological and mating compatibility data, an example of ecotypic differentiation and speciation within an endemic pelagic inhabitant, the diatom Fragilariopsis kerguelensis. We discovered three genotypic variants, one present throughout the latitudinal transect sampled, the others restricted to the north and south, respectively. The latter two showed reciprocal monophyly across all three genomes and significant ecophysiological differences consistent with local adaptation, but produced viable offspring in laboratory crosses. The third group was also reproductively isolated from the latter two. We hypothesize that this pattern originated by an adaptive expansion accompanied by ecotypic divergence, followed by sympatric speciation.