Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), P. O. Box 0843-01103, Panama, Panama; Department of Biotechnology, Acharya Nagarjuna University, Guntur, India; Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Balboa Ancón, Panama, Panama.
Sam Noble Oklahoma Museum of Natural History and Department of Biology, University of Oklahoma, Norman, OK, USA.
Gene. 2019 Feb 20;686:164-170. doi: 10.1016/j.gene.2018.11.045. Epub 2018 Nov 16.
Electric fishes are a diverse group of freshwater organisms with the ability to generate electric organ discharges (EODs) that are used for communication and electrolocation. This group (ca. 200 species) has originated in South America, and six species colonized the Central American Isthmus. Here, we assembled the complete mitochondrial genomes (mitogenomes) for three Central American electric fishes (i.e. Sternopygus dariensis, Brachyhypopomus occidentalis, and Apteronotus rostratus), and, based on these data, explored their phylogenetic position among Gymnotiformes. The three mitogenomes show the same gene order, as reported for other fishes, with a size ranging from 16,631 to 17,093 bp. We uncovered a novel 60 bp intergenic spacer (IGS) located between the COII and tRNA genes, which appears to be unique to the Apteronotidae. Furthermore, phylogenetic relationships supported the traditional monophyly of Gymnotiformes, with the three species positioned within their respective family. In addition, the genus Apteronotus belongs to the early diverging lineage of the order. Finally, we found high sequence divergence (13%) between our B. occidentalis specimen and a sequence previously reported in GenBank, suggesting that the prior mitogenome of B. occidentalis represents a different South American species. Indeed, phylogenetic analyses using Cytochrome b gene across the genus placed the previously reported individual within B. bennetti. Our study provides novel mitogenome resources that will advance our understanding of the diversity and phylogenetic history of Neotropical fishes.
电鱼是一个具有产生电器官放电（EOD）能力的淡水生物多样性群体，这种放电能力用于通讯和电定位。这个群体（约 200 种）起源于南美洲，有 6 个种在中美洲地峡进行了殖民化。在这里，我们为三种中美洲电鱼（即 Sternopygus dariensis、Brachyhypopomus occidentalis 和 Apteronotus rostratus）组装了完整的线粒体基因组（mitogenomes），并基于这些数据探索了它们在 Gymnotiformes 中的系统发育位置。这三个 mitogenomes 显示出与其他鱼类相同的基因顺序，大小从 16631 到 17093bp 不等。我们发现了一个位于 COII 和 tRNA 基因之间的新的 60bp 基因间隔（IGS），这似乎是 Apteronotidae 所特有的。此外，系统发育关系支持 Gymnotiformes 的传统单系性，这三种鱼类位于各自的科内。此外，Apteronotus 属属于该目早期分化的谱系。最后，我们发现我们的 B. occidentalis 标本与 GenBank 中先前报道的序列之间存在高度的序列差异（13%），这表明之前报道的 B. occidentalis 的 mitogenome 代表了一个不同的南美洲物种。事实上，使用细胞色素 b 基因在属内进行的系统发育分析将先前报道的个体置于 B. bennetti 内。我们的研究提供了新的 mitogenome 资源，将促进我们对新热带鱼类多样性和系统发育历史的理解。
