National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, 316022 Zhoushan, China; Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Beibu Gulf Marine Research Center, Guangxi Academy of Sciences, Nanning 530007, China.
National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, 316022 Zhoushan, China.
Int J Biol Macromol. 2020 Apr 15;149:1232-1240. doi: 10.1016/j.ijbiomac.2020.02.017. Epub 2020 Feb 4.
Mitochondrial genome (mitogenome) structure and gene order are generally considered conserved in vertebrates. However, the flatfish (Pleuronectiformes) mitogenomes exhibit the most diversified gene rearrangement patterns. Here, we report a newly sequenced mitogenome of Cynoglossus melampetalus (Pleuronectiformes: Cynoglossidae). The total length of the C. melampetalus mitogenome is 16,651 bp, containing 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNAs, a putative control region, and an L-strand replication origin. Like all previously reported tongue sole (Cynoglossinae) mitogenomes, the C. melampetalus tRNA-Gln gene is inverted from the light to the heavy strand (Q inversion), accompanied by the translocation of CR, which is downstream to the 3'-end of ND1. In addition, we observed a unique tRNA-Ile-Met-Glu (IMQ) gene order that differed from the tRNA-Glu-Ile-Met (QIM) order previously reported for other 14 Cynoglossinae mitogenomes. To our knowledge, it is the first report of two different patterns of mitogenomic gene-arrangement within the same genus in teleost. According to the Q inversion, Met pseudogene (ψMet) and long intergenic gap (186 bp) between M and Q genes, the observed gene rearrangement pattern were presumably supported by mitochondrial recombination and tandem duplication/random loss models. The reduced trend of the intergenic gap between Q and I also suggests that the event of gene rearrangement can be traced back to early Cynoglossinae differentiation.
线粒体基因组（mitogenome）结构和基因顺序通常被认为在脊椎动物中是保守的。然而，比目鱼（鲽形目）的线粒体基因组表现出最多样化的基因重排模式。在这里，我们报告了一条新测序的圆斑星鲽（鲽形目：舌鳎科）的线粒体基因组。圆斑星鲽的线粒体基因组总长为 16651bp，包含 13 个蛋白质编码基因、两个核糖体 RNA、22 个转移 RNA、一个假定的控制区和一个 L 链复制起点。与所有先前报道的舌鳎（舌鳎科）线粒体基因组一样，圆斑星鲽的 tRNA-Gln 基因从轻链到重链（Q 反转）发生反转，伴随着 CR 的易位，该易位位于 ND1 的 3'末端下游。此外，我们观察到一个独特的 tRNA-Ile-Met-Glu（IMQ）基因顺序，与先前报道的其他 14 种舌鳎科线粒体基因组中的 tRNA-Glu-Ile-Met（QIM）顺序不同。据我们所知，这是在同一鱼类属内首次报道两种不同的线粒体基因组基因排列模式。根据 Q 反转、Met 假基因（ψMet）和 M 与 Q 基因之间的长基因间间隔（186bp），观察到的基因重排模式可能是由线粒体重组和串联重复/随机丢失模型支持的。Q 与 I 之间基因间间隔的减少趋势也表明，基因重排事件可以追溯到早期舌鳎科的分化。
