Zhang Xiaoli, Jia Shuang-Xi, Sun Cheng-He
College of Environment and Life Health, Anhui Vocational and Technical College, Hefei, China.
College of Life Sciences, Nanjing Forestry University, Nanjing, China.
Front Genet. 2025 Aug 29;16:1623517. doi: 10.3389/fgene.2025.1623517. eCollection 2025.
Traditional classifications of New World cichlids have been subject to persistent controversy. Within the genus , only two species are currently recognized; however, complete mitochondrial sequences for these taxa have remained unavailable. In the present study, we sequenced and characterized the complete mitochondrial genome of This mitogenome has a total length of 16,621 bp and encodes the standard 37 genes found in vertebrate mitochondria: 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and one non-coding control region (D-loop). Among the PCGs, only Cox1 gene utilizes GTG as its start codon, while the remaining 12 PCGs start with ATG. Observed termination codons included TAA, AGA, TAG, and the incomplete codons TA and T. The overall base composition of the mitochondrial sequence exhibits an A + T bias, with a combined A + T content of 54.1%. In this study, the high mitogenome similarity observed among several species in this study resulted from interspecific hybridization rather than synonymy or taxonomic misidentification. Maximum likelihood and Bayesian inference evolutionary trees were constructed using mitochondrial genome sequences from 44 Cichlidae species. Phylogenetic analyses consistently recovered the tribes Geophaginae, Cichlasomatinae, and Cichlinae as monophyletic groups. In contrast, the tribe Astronotinae was recovered as polyphyletic. These results clarify the evolutionary position of within New World cichlids and will contribute to elucidating the complex phylogenetic relationships among cichlid species.
新世界丽鱼科鱼类的传统分类一直存在持续的争议。在该属中，目前仅确认了两个物种；然而，这些分类单元的完整线粒体序列仍然无法获得。在本研究中，我们对[物种名称未给出]的完整线粒体基因组进行了测序和特征分析。这个线粒体基因组全长16,621 bp，编码脊椎动物线粒体中常见的37个标准基因：13个蛋白质编码基因（PCGs）、22个转移RNA（tRNA）基因、两个核糖体RNA（rRNA）基因和一个非编码控制区（D-loop）。在PCGs中，只有Cox1基因以GTG作为起始密码子，而其余12个PCGs以ATG起始。观察到的终止密码子包括TAA、AGA、TAG以及不完整的密码子TA和T。[物种名称未给出]线粒体序列的总体碱基组成表现出A + T偏向性，A + T的总含量为54.1%。在本研究中，观察到的几个物种之间线粒体基因组的高度相似性是由于种间杂交而非同义性或分类错误鉴定导致的。使用44种丽鱼科物种的线粒体基因组序列构建了最大似然法和贝叶斯推断进化树。系统发育分析一致将食土丽鱼亚科、丽体鱼亚科和丽鱼亚科作为单系类群。相比之下，星丽鱼亚科被发现是多系的。这些结果阐明了[物种名称未给出]在新世界丽鱼科鱼类中的进化位置，并将有助于阐明丽鱼科物种之间复杂的系统发育关系。
