Molecular phylogeny of Squaliformes and first occurrence of bioluminescence in sharks.
Molecular phylogeny of Squaliformes and first occurrence of bioluminescence in sharks.
复制标题
角鲨目的分子系统发育和鲨鱼生物发光的首次出现。
DOI：
10.1186/s12862-015-0446-6
复制
发表时间：
2015-08-16
影响因子：
3.4
通讯作者：
Naylor GJ
中科院分区：
文献类型：
--
作者：
Straube N;Li C;Claes JM;Corrigan S;Naylor GJ
角鲨约占现存鲨鱼多样性的27%，包括130多个物种，主要生活在深海。许多角鲨目的鲨鱼都是高度特化的，包括一些会发光的生物，这种特性只在软骨鱼纲的角鲨中发现。但该组织内部的关系仍然没有得到满意的解决。在这里，我们估计系统发育的相互关系的一个属级采样的“角鲨”鲨鱼和密切相关的类群使用对齐序列来自有针对性的基因捕获方法。由此产生的系统发育估计进一步用于评估的年龄首次出现的生物发光的角形目。我们的数据集包括172个假定的直系同源外显子序列。系统发育的估计结果在一个完全解决的树支持一个单系谱系的角形目不包括Echinorhinus。不发光的角鲨科被推断为一个分支的姐妹，该分支包括所有剩余的角鲨科。我们的研究结果表明，的起源是一致的高多样化率和分裂的家庭Dalatiidae，Etmopteridae，Oxynotidae和Somniosidae在下白垩纪到上白垩纪的过渡。发光器官的存在被确认为睡眠鲨鱼属Zameus。这些结果表明，鲨鱼的生物发光不仅限于家庭Etmopteridae和Dalatiidae以前认为。非发光角鲨科的姐妹分支由五个科组成。根据这项研究的结果，在这五个科中有三个科的现存成员报告说，有鲨鱼，即灯笼鲨（Etmopteridae）、鸢鳍鲨（Dalatiidae）和睡鲨（Somniosidae）。我们的研究结果表明，发光器官的起源出现在快速多样化的事件，引起了现存的角鲨科。这些推论是一致的，与出现新的深海栖息地在下白垩纪，这可能是由生物发光的进化促进了角鲨的多样化的想法。本文的在线版本（doi：10.1186/s12862-015-0446-6）包含补充材料，可供授权用户使用。
Squaliform sharks represent approximately 27 % of extant shark diversity, comprising more than 130 species with a predominantly deep-dwelling lifestyle. Many Squaliform species are highly specialized, including some that are bioluminescent, a character that is reported exclusively from Squaliform sharks within Chondrichthyes. The interfamiliar relationships within the order are still not satisfactorily resolved. Herein we estimate the phylogenetic interrelationships of a generic level sampling of “squaloid” sharks and closely related taxa using aligned sequences derived from a targeted gene capture approach. The resulting phylogenetic estimate is further used to evaluate the age of first occurrence of bioluminescence in Squaliformes. Our dataset comprised 172 putative ortholog exon sequences. Phylogenetic estimates result in a fully resolved tree supporting a monophyletic lineage of Squaliformes excluding Echinorhinus. Non-luminous Squalidae are inferred to be the sister to a clade comprising all remaining Squaliform families. Our results suggest that the origin of photophores is coincident with an elevated diversification rate and the splitting of families Dalatiidae, Etmopteridae, Oxynotidae and Somniosidae at the transition of the Lower to the Upper Cretaceous. The presence of luminous organs was confirmed for the Sleeper shark genus Zameus. These results indicate that bioluminescence in sharks is not restricted solely to the families Etmopteridae and Dalatiidae as previously believed. The sister-clade to non-luminous Squalidae comprises five families. The presence of photophores is reported for extant members of three out of these five families based on results of this study, i.e. Lantern sharks (Etmopteridae), Kitefin sharks (Dalatiidae) and Sleeper sharks (Somniosidae). Our results suggest that the origin of luminous organs arose during the rapid diversification event that gave rise to the extant Squaliform families. These inferences are consistent with the idea of diversification of Squaliform sharks being associated with the emergence of new deep-sea habitats in the Lower Cretaceous, which may have been facilitated by the evolution of bioluminescence. The online version of this article (doi:10.1186/s12862-015-0446-6) contains supplementary material, which is available to authorized users.