Gubili Chrysoula, Seitidou Orezia, Batista Romina, Papadopoulou Paraskevi, Christidis Aris, Triantafillidis Stelios, Sapounidis Argyrios
Fisheries Research Institute, Hellenic Agricultural Organisation-DIMITRA, Nea Peramos, Kavala, 64007, Greece.
School of Science, Engineering, and Environment, University of Salford, Salford, M5 4WT, UK.
Mol Biol Rep. 2025 Apr 5;52(1):363. doi: 10.1007/s11033-025-10476-5.
The genus Caspiomyzon is comprised of three species, two of which are found in Greece (Caspiomyzon hellenicus and Caspiomyzon graecus). Both species are endemic with very restricted distribution and are classified as Critically Endangered. Caspiomyzon hellenicus is restricted to Tenagi, Philippi and C. graecus to Louros River. No studies have characterized their mitochondrial genomes.
The complete mitochondrial genome of C. hellenicus and C. graecus was generated with Oxford Nanopore long-read technology, and it was processed using various bioinformatics approaches. The final assembled contig length was 16,763 bp and 17,123 bp, respectively, and composed of 13 protein-coding genes, two ribosomal RNA genes, 22 tRNA genes, and two control regions. Repetitive sequences were detected between and within the control regions. The overall GC composition was approximately 36% for both species. The results of phylogenetics analysis using Bayesian inference and Maximum likelihood methods revealed that the Geotria australis species was sister to northern hemisphere lampreys, whereas Mordacia species constitutes a monophyletic group. Divergence time between the Greek Caspiomyzon species took place at approximately 0.7 Mya.
This study enhanced our understanding of the taxonomic and phylogenetic relationships within the Caspiomyzon genus from Greece based on the characterization of the full mitochondrial genomes from long-reads technology. Such efforts can aid their conservation and management locally.
卡斯皮七鳃鳗属由三个物种组成，其中两个发现于希腊（希腊卡斯皮七鳃鳗和希腊格雷克七鳃鳗）。这两个物种均为特有种，分布范围极为有限，被列为极度濒危物种。希腊卡斯皮七鳃鳗仅限于泰纳吉、菲利普，而希腊格雷克七鳃鳗仅限于卢罗斯河。尚无研究对它们的线粒体基因组进行表征。
利用牛津纳米孔长读长技术生成了希腊卡斯皮七鳃鳗和希腊格雷克七鳃鳗的完整线粒体基因组，并采用各种生物信息学方法对其进行处理。最终组装的重叠群长度分别为16,763 bp和17,123 bp，由13个蛋白质编码基因、两个核糖体RNA基因、22个tRNA基因和两个控制区组成。在控制区之间和内部检测到重复序列。两个物种的总体GC含量约为36%。使用贝叶斯推断和最大似然法进行系统发育分析的结果表明，澳大利亚七鳃鳗物种是北半球七鳃鳗的姐妹物种，而莫尔达西亚七鳃鳗物种构成一个单系类群。希腊卡斯皮七鳃鳗物种之间的分化时间约在0.7百万年前。
本研究基于长读长技术对完整线粒体基因组的表征，增强了我们对希腊卡斯皮七鳃鳗属内分类学和系统发育关系的理解。这些努力有助于当地对它们的保护和管理。
