Evolution of nuchal glands, unusual defensive organs of Asian natricine snakes (Serpentes: Colubridae), inferred from a molecular phylogeny.
Evolution of nuchal glands, unusual defensive organs of Asian natricine snakes (Serpentes: Colubridae), inferred from a molecular phylogeny.
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DOI：
10.1002/ece3.4497
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发表时间：
2018-10
影响因子：
2.6
通讯作者：
Mori A
中科院分区：
文献类型：
--
作者：
Takeuchi H;Savitzky AH;Ding L;de Silva A;Das I;Nguyen TT;Tsai TS;Jono T;Zhu GX;Mahaulpatha D;Tang Y;Mori A
大量的证据表明，新器官的进化创新促进了随后的物种多样化。对这些器官进化历史的调查应该为理解物种多样化的基础提供重要线索。一种亚洲的天然蛇，虎斑游蛇，拥有一系列不寻常的器官，称为项腺，其中含有强心类固醇毒素，称为蟾蜍二烯内酯。虎斑槽蛇从蟾蜍猎物中提取蟾蜍二烯内酯，并将其储存在项腺中作为防御机制。在3,500多种蛇类中，已知只有17种亚洲蛇类拥有颈腺或其同源物。这17个物种属于三个名义属：蛇鳗属、大鳞蛇属和杆蛇属。然而，在Macropisthodon和Rhabdophis中，也存在没有颈腺的物种。为了推断项腺的进化历史，我们基于Mt-CYB、Cmos和RAG 1部分序列的变异（总长度为2,767 bp），研究了有和没有项腺的亚洲natricine物种之间的分子系统发育关系。结果表明，所有具有项腺的物种都属于一个分支（NGC）。因此，我们推断这个分支的共同祖先具有颈部腺体，成员内的腺体没有独立的起源。我们的研究结果还表明，一些物种已经继发性地失去了腺体。考虑到相关物种的分歧时间估计，颈腺分支的祖先出现了19.18百万年。我们的研究表明，项腺是探索新器官进化的富有成效的主题。此外，我们的分析表明，需要重新评估的属Balanophis和Macropisthodon的分类地位。我们建议将所有属于NGC的物种归为Rhabdophis属，有待进一步研究。
A large body of evidence indicates that evolutionary innovations of novel organs have facilitated the subsequent diversification of species. Investigation of the evolutionary history of such organs should provide important clues for understanding the basis for species diversification. An Asian natricine snake, Rhabdophis tigrinus, possesses a series of unusual organs, called nuchal glands, which contain cardiotonic steroid toxins known as bufadienolides. Rhabdophis tigrinus sequesters bufadienolides from its toad prey and stores them in the nuchal glands as a defensive mechanism. Among more than 3,500 species of snakes, only 17 Asian natricine species are known to possess nuchal glands or their homologues. These 17 species belong to three nominal genera, Balanophis, Macropisthodon, and Rhabdophis. In Macropisthodon and Rhabdophis, however, species without nuchal glands also exist. To infer the evolutionary history of the nuchal glands, we investigated the molecular phylogenetic relationships among Asian natricine species with and without nuchal glands, based on variations in partial sequences of Mt‐CYB, Cmos, and RAG1 (total 2,767 bp). Results show that all species with nuchal glands belong to a single clade (NGC). Therefore, we infer that the common ancestor of this clade possessed nuchal glands with no independent origins of the glands within the members. Our results also imply that some species have secondarily lost the glands. Given the estimated divergence time of related species, the ancestor of the nuchal gland clade emerged 19.18 mya. Our study shows that nuchal glands are fruitful subjects for exploring the evolution of novel organs. In addition, our analysis indicates that reevaluation of the taxonomic status of the genera Balanophis and Macropisthodon is required. We propose to assign all species belonging to the NGC to the genus Rhabdophis, pending further study.
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影响因子：
4.1
作者：
Castoe, TA;Parkinson, CL
通讯作者：
Parkinson, CL
影响因子：
4.1
作者：
Lawson, R;Slowinski, JB;Burbrink, FT
通讯作者：
Burbrink, FT
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作者：
Guicking, Daniela;Joger, Ulrich;Wink, Michael
通讯作者：
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3.7
作者：
Figueroa A;McKelvy AD;Grismer LL;Bell CD;Lailvaux SP
通讯作者：
Lailvaux SP
影响因子：
4.1
作者：
Alfaro, ME;Arnold, SJ
通讯作者：
Arnold, SJ