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Molecular evolution of bivalvian mtDNA and its systematic significance

双壳类线粒体DNA的分子进化及其系统意义

基本信息

批准号：
13440251
负责人：
UESHIMA Rei
金额：
$ 9.47万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440251/
关键词：
Bivalve mtDNA genome mode of inheritance evolution ゲノム構造

项目摘要

Metazoan mitochondrial genome encodes 13 protein genes, 2 rRNA genes and 22 tRNA genes. The gene arrangements and gene contents are usually conserved among different phyla. However, mtDNA of Mytilus edulis, a bivalve mollusca, shows a distinct gene arrangements with the unusual gene contents lacking ATPase 8 gene. In addition, Mytilus mtDNA is demonstrated to be inherited biparentally, while mtDNA is inherited maternally in all other metazoans. It is remained to be solved whether such unusual genome structure or mode of inheritance are universal for bivalve mollusca or specific to Mytilus. In the present study, we examined mt-gene arrangement and mtDNA inheritance for various bivalve taxa of the subclass Protobranchia, Pteriomorpha, Heterodonta, Palaeoheterodonta and Anomalodesmata.We detected presence of sex-specific mtDNAs in heterodont bivalves. Their gender association and tissue specificity are concordant with those found in Mytilus. Molecular phylogenetic analysis suggests frequent parallel evolution of male-specific mtDNA lineages.We could determine partial mt-gene arrangement for 8 different bivalve taxa. In higher bivalves, the gene arrangements and gene contents differs substantially among taxa. On the other hand, protobranch bivalves retain ancestral genome structure which shares many gene arrangements and normal gene contents with other phyla. In bivalves, mitochondrial genome structures should be derived from protobranch-like ancester and the unique gene orders and contents may be evolved independently in various higher taxa.

后生动物线粒体基因组编码13个蛋白基因、2个rRNA基因和22个tRNA基因。基因排列和基因含量在不同门之间通常是保守的。然而，双壳类软体动物Mytilus edulis的mtDNA却显示出独特的基因排列，其异常的基因含量缺乏atp酶8基因。此外，Mytilus mtDNA被证明是双亲本遗传的，而mtDNA在所有其他后生动物中都是母本遗传的。这种不寻常的基因组结构或遗传方式是双壳类软体动物普遍存在的，还是为鹦鹉螺所特有的，还有待解决。本文对原鳃亚纲、翼形亚纲、异齿亚纲、古异齿亚纲和异齿亚纲中不同双壳类的mtDNA序列和遗传进行了研究。我们在异卵双壳类动物中检测到了性别特异性mtdna的存在。它们的性别关联和组织特异性与Mytilus一致。分子系统发育分析表明，男性特有的mtDNA谱系经常平行进化。我们可以确定8个不同双壳类动物的部分mt-基因排列。在高等双壳类动物中，不同分类群的基因排列和基因含量差异很大。另一方面，原分支双壳类动物保留了祖先的基因组结构，与其他门具有许多相同的基因排列和正常的基因含量。双壳类动物线粒体基因组结构可能来源于原枝样祖先，其独特的基因序列和内容可能在不同高等分类群中独立进化而来。