摘要
Deep-sea organisms survive in an extremely harsh environment.There must be some genetic adaptation mechanisms for them.We systematically characterized and compared the complete mitochondrial genome(mitogenome)of a deep-sea crab(Chaceon granulates)with those of shallow crabs.The mitogenome of the crab was 16126 bp in length,and encoded 37 genes as most of a metazoan mitogenome,including 13 protein-coding genes(PCGs),22 transfer RNA(tRNA)genes,and 2 ribosomal RNA(rRNA)genes.The gene arrangement and orientation was conserved in the crabs.However,a unique mitogenome element regulator,the origin of light-strand replication(O L),was firstly predicted in the present crab mitogenome.In addition,further positive selection analysis showed that two residues(33 S in ND3 and 502 I in ND5)in C.granulates mitogenome were positively selected,indicated the selective evolution of the deep-sea crab.Therefore,the mitogenome of deep-sea C.granulates showed a unique OL element and positive selection.These special features would influence the mitochondrial energy metabolism,and be involved in the adaptation of deepsea environment,such as oxygen deficits and low temperatures.
Deep-sea organisms survive in an extremely harsh environment.There must be some genetic adaptation mechanisms for them.We systematically characterized and compared the complete mitochondrial genome(mitogenome) of a deep-sea crab(Chaceon granulates) with those of shallow crabs.The mitogenome of the crab was 16 126 bp in length,and encoded 37 genes as most of a metazoan mitogenome,including 13 protein-coding genes(PCGs),22 transfer RNA(tRNA) genes,and 2 ribosomal RNA(rRNA) genes.The gene arrangement and orientation was conserved in the crabs.However,a unique mitogenome element regulator,the origin of light-strand replication(O L),was firstly predicted in the present crab mitogenome.In addition,further positive selection analysis showed that two residues(33 S in ND3 and 502 I in ND5) in C.granulates mitogenome were positively selected,indicated the selective evolution of the deep-sea crab.Therefore,the mitogenome of deep-sea C.granulates showed a unique O_L element and positive selection.These special features would influence the mitochondrial energy metabolism,and be involved in the adaptation of deepsea environment,such as oxygen deficits and low temperatures.
基金
Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA13020103,XDA19060301)
the National Science&Technology Fundamental Resources Investigation Program of China(No.2018FY100106)
the National Key Research and Development Program “Marine Environment Security Project”(Nos.2017YFC0506302,2018YFC1406503)
