Solemyidae is an ancient group of protobranch bivalves,and most solemyids are symbiotic with chemoautotrophic and gill-hosted bacteria,enabling them to survive in unusual habitats such as deepsea chemosynthetic enviro...Solemyidae is an ancient group of protobranch bivalves,and most solemyids are symbiotic with chemoautotrophic and gill-hosted bacteria,enabling them to survive in unusual habitats such as deepsea chemosynthetic environments.However,evolution of the mitogenomes in this family and their phylogenetic relationships remain poorly understood.The complete mitogenome of Acharax sp.was determined and compared with other available mitogenomes of solemyids.The mitogenome of Acharax sp.is 18970 bp in length and consists of 13 protein-coding genes,2 ribosomal RNA genes,and 22 transfer RNA genes.The gene arrangement was identical to those of other sequenced solemyids.For the present five mitogenomes of Solemyidae species,all protein-coding genes were initiated with the typical ATD(ATA,ATG,and ATT)codon and terminated with the TAA/TAG codon.Furthermore,the incomplete termination codon was detected.The Ka/Ks ratio analyses indicated that 13 protein-coding genes of five Solemyidae mitogenomes suffered strong purifying selection.Compared to 45 existing shallow water equivalents,the 18 available mitogenomes from the deep-sea,including the Acharax sp.in this study,show significantly more nonpolar amino acids in the 13 protein-coding genes,which indicates the adaptation to the deep-sea environment.The phylogenetic tree based on 48 Bivalvia complete mitogenomes provided further information to support the scientific classification of protobranchs.The relationships among Solemyidae were assessed based on 2 mitochondrial(16S rRNA and COX1)and 3 nuclear(18S rRNA,28S rRNA,and histone H3)gene sequences from 17 in-group species.The two genera Acharax and Solemya formed a monophyletic clade each,and Acharax sp.clustered with previously reported Acharax bivalves with high support values.展开更多
基金Supported by the Senior User Project of R/V Kexue(No.KEXUE2020GZ01)the National Natural Science Foundation of China(No.42176114)。
文摘Solemyidae is an ancient group of protobranch bivalves,and most solemyids are symbiotic with chemoautotrophic and gill-hosted bacteria,enabling them to survive in unusual habitats such as deepsea chemosynthetic environments.However,evolution of the mitogenomes in this family and their phylogenetic relationships remain poorly understood.The complete mitogenome of Acharax sp.was determined and compared with other available mitogenomes of solemyids.The mitogenome of Acharax sp.is 18970 bp in length and consists of 13 protein-coding genes,2 ribosomal RNA genes,and 22 transfer RNA genes.The gene arrangement was identical to those of other sequenced solemyids.For the present five mitogenomes of Solemyidae species,all protein-coding genes were initiated with the typical ATD(ATA,ATG,and ATT)codon and terminated with the TAA/TAG codon.Furthermore,the incomplete termination codon was detected.The Ka/Ks ratio analyses indicated that 13 protein-coding genes of five Solemyidae mitogenomes suffered strong purifying selection.Compared to 45 existing shallow water equivalents,the 18 available mitogenomes from the deep-sea,including the Acharax sp.in this study,show significantly more nonpolar amino acids in the 13 protein-coding genes,which indicates the adaptation to the deep-sea environment.The phylogenetic tree based on 48 Bivalvia complete mitogenomes provided further information to support the scientific classification of protobranchs.The relationships among Solemyidae were assessed based on 2 mitochondrial(16S rRNA and COX1)and 3 nuclear(18S rRNA,28S rRNA,and histone H3)gene sequences from 17 in-group species.The two genera Acharax and Solemya formed a monophyletic clade each,and Acharax sp.clustered with previously reported Acharax bivalves with high support values.
