Environmental specialization and cryptic genetic divergence in two massive coral species from the Florida Keys Reef Tract
Environmental specialization and cryptic genetic divergence in two massive coral species from the Florida Keys Reef Tract
复制标题
DOI：
10.1111/mec.15931
复制
发表时间：
2020-11
期刊：
影响因子：
--
通讯作者：
J. Rippe;G. Dixon;Zachary L. Fuller;Yi Liao;M. Matz
中科院分区：
文献类型：
--
作者：
J. Rippe;G. Dixon;Zachary L. Fuller;Yi Liao;M. Matz
广播产卵珊瑚物种有广泛的地理范围，跨越强烈的环境梯度，但目前还不清楚有多少空间变化的选择这些梯度实际上施加。强大的分歧选择可能会提出一个相当大的障碍，不同的珊瑚礁栖息地之间的人口交换。我们调查了跨大陆架梯度（近岸-近海-深水）是否与两种常见珊瑚物种（Montastraea cavernosa和Siderastrea siderea）在佛罗里达礁群中的空间变化选择相关。为此，我们为M. cavernosa和使用2bRAD基因型20青少年和20成年人的两个物种从每个三个珊瑚礁区，以确定签名的选择发生在一个单一的一代。出乎意料的是，每个物种都被发现由四个遗传上不同的谱系组成，它们之间的基因流动仍然在进行，但在13.0-54.7%的基因组中高度减少。每个物种包括两个同域谱系，只在深（20米）栖息地发现，而其他谱系几乎只在较浅的珊瑚礁（3-10米）发现。M.海绵体动物也专门用于近岸或近海：成年和少年群体之间的比较表明，跨大陆架移徙者在成年前死亡的可能性是当地新兵的两倍多。Siderastreasiderea和M. cavernosa是其中最生态成功的物种退化佛罗里达礁岛域，这项工作提供了重要的见解基因组背景的不同选择和环境专业化，可能在一定程度上解释他们的弹性和广泛的环境范围。
Broadcast-spawning coral species have wide geographic ranges, spanning strong environmental gradients, but it is unclear how much spatially varying selection these gradients actually impose. Strong divergent selection might present a considerable barrier for demographic exchange between disparate reef habitats. We investigated whether the cross-shelf gradient (nearshore - offshore - deep) is associated with spatially varying selection in two common coral species, Montastraea cavernosa and Siderastrea siderea, in the Florida Keys. Toward this end, we generated a de novo genome assembly for M. cavernosa and used 2bRAD to genotype 20 juveniles and 20 adults of both species from each of the three reef zones to identify signatures of selection occurring within a single generation. Unexpectedly, each species was found to be composed of four genetically distinct lineages, with gene flow between them still ongoing but highly reduced in 13.0-54.7% of the genome. Each species includes two sympatric lineages that are only found in the deep (20 m) habitat, while the other lineages are found almost exclusively on the shallower reefs (3-10 m). The two “shallow” lineages of M. cavernosa are also specialized for either nearshore or offshore: comparison between adult and juvenile cohorts indicates that cross-shelf migrants are more than twice as likely to die before reaching adulthood than local recruits. Siderastrea siderea and M. cavernosa are among the most ecologically successful species on the degraded Florida Keys Reef Tract, and this work offers important insight on the genomic background of divergent selection and environmental specialization that may in part explain their resilience and broad environmental range.