Department of Biological Sciences, Sungkyunkwan University, 2066 Seobu-ro, Suwon, Gyeonggi-do 16419, Republic of Korea.
Division of EcoScience, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Republic of Korea.
Mol Phylogenet Evol. 2019 Oct;139:106533. doi: 10.1016/j.ympev.2019.106533. Epub 2019 Jun 8.
The family Mytilidae is a family of bivalve mussels that are distributed worldwide in diverse marine habitats. Within the family, classification systems and phylogenetic relationships among subfamilies remain not yet fully resolved. In this study, we newly determined 9 mitochondrial genome sequences from 7 subfamilies: Bathymodiolus thermophilus (Bathymodiolinae), Modiolus nipponicus (Modiolinae), Lithophaga curta (the first representative of Lithophaginae), Brachidontes mutabilis (Brachidontinae), Mytilisepta virgata (Brachidontinae), Mytilisepta keenae (Brachidontinae), Crenomytilus grayanus (Mytilinae), Gregariella coralliophaga (Crenellinae), and Septifer bilocularis (the first representative of Septiferinae). Phylogenetic trees using maximum likelihood and Bayesian inference methods for 28 mitochondrial genomes (including 19 previously published sequences) showed two major clades with high support values: Clade 1 ((Bathymodiolinae + Modiolinae) + (Lithophaginae + Limnoperninae)) and Clade 2 (((Mytilinae + Crenellinae) + Septiferinae) + Brachidontinae). The position of the genus Lithophaga (representing Lithophaginae) differed from a previously published molecular phylogeny. Divergence time analysis with a molecular clock indicated that lineage splitting among the major subfamilies of Mytilidae (including the habitat transition from marine to freshwater environments by ancestral Limnoperninae) occurred in the Mesozoic period, coinciding with high diversification rates of marine fauna during that time. This is the first mitochondrial genome-based phylogenetic study of the Mytilidae that covers nearly all subfamily members, excluding the subfamily Dacrydiinae.
贻贝科是分布于全球各种海洋生境中的双壳贝类家族。在该科中，亚科的分类系统和系统发育关系尚未完全解决。在这项研究中，我们从 7 个亚科中新确定了 9 个线粒体基因组序列：深海热液蛤（深海蛤亚科）、日本贻贝（贻贝亚科）、短石蛏（石蛏亚科的第一个代表）、扁蜾蠃蜚（蜾蠃蜚亚科）、弯贻贝（蜾蠃蜚亚科）、贻贝拟甲（蜾蠃蜚亚科）、灰厚壳贻贝（贻贝亚科）、珊瑚枝孔贝（棱齿蛤亚科）和双壳贝（双壳贝亚科的第一个代表）。使用最大似然法和贝叶斯推断法对 28 个线粒体基因组（包括 19 个已发表序列）构建的系统发育树显示出两个具有高支持值的主要分支：分支 1（（深海蛤亚科+贻贝亚科）+（石蛏亚科+Limnoperninae 亚科））和分支 2（（贻贝亚科+棱齿蛤亚科）+（双壳贝亚科））。石蛏属（代表石蛏亚科）的位置与之前发表的分子系统发育结果不同。分子钟的分歧时间分析表明，贻贝科主要亚科（包括祖先 Limnoperninae 从海洋向淡水环境的栖息地转变）的谱系分化发生在中生代，与当时海洋动物的高多样化率相吻合。这是首次基于线粒体基因组对涵盖除 Dacrydiinae 亚科以外的贻贝科的系统发育进行的研究。
