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Gene Rearrangements and Evolution of tRNA Pseudogenes in the Mitochondrial Genome of the Parrotfish (Teleostei: Perciformes: Scaridae)
- Source :
- Journal of Molecular Evolution. 59:287-297
- Publication Year :
- 2004
- Publisher :
- Springer Science and Business Media LLC, 2004.
-
Abstract
- Genomic size of animal mitochondrial DNA is usually minimized over time. Thus, when regional duplications occur, they are followed by a rapid elimination of redundant material. In contrast to this general view, we report here long-sustained tRNA pseudogenes in the mitochondrial genome (mitogenome) of teleost fishes of the family Scaridae (parrotfishes). During the course of a molecular phylogenetic study of the suborder Labroidei, we determined the complete nucleotide sequence of the mitogenome for a parrotfish, Chlorurus sordidus, and found a gene rearrangement accompanied by a tRNA pseudogene. In the typical gene order of vertebrates, a tRNA-gene cluster between ND1 and ND2 genes includes tRNA(Ile) (I), tRNA(Gln) (Q), and tRNA(Met) (M) genes in this order (IQM). However, in the mitogenome of the parrotfish, the tRNA(Met) gene was inserted between the tRNA(Ile) and the tRNA(Gln) genes, and the tRNA(Gln) gene was followed by a putative tRNA(Met) pseudogene (psiM). Such a tRNA gene rearrangement including a pseudogene (IMQpsiM) was found in all of the 10 examined species, representing 7 of the 10 currently recognized scarid genera. All sister groups examined (20 species of Labridae and a single species of Odacidae) had the typical gene order of vertebrate mitogenomes. Phylogenetic analysis of the tRNA(Met) genes and the resulting pseudogenes demonstrated that the ancestral tRNA(Met) gene was duplicated in a common ancestor of the parrotfish. Based on the fossil record, these results indicate that the pseudogenes have survived at least 14 million years. Most of the vertebrate mitochondrial gene rearrangements involving the IQM region have held the tRNA(Met) gene just upstream of the ND2 gene, and even in a few exceptional cases, including the present ones, the tRNA pseudogenes have been found in that position. In addition, most of these tRNA(Met) pseudogenes maintained clover-leaf secondary structures, with the remainder sustaining the clover-leaf structure in the "top half (TpsiC and acceptor arms). Considering their potential secondary structures (holding "top halves" of the clover-leaf structures), locations within mitogenomes (flanking the 5' ends of the ND2 genes) and stabilities over time (survived at least 14 Myr), it is likely that the tRNA pseudogenes retain function as punctuation marks for mitochondrial ND2 mRNA processing.
- Subjects :
- Mitochondrial DNA
Pseudogene
Molecular Sequence Data
Biology
DNA, Mitochondrial
Evolution, Molecular
RNA, Transfer
Genes, Duplicate
Gene Order
Genetics
Animals
Cluster Analysis
Amino Acid Sequence
Base Pairing
Molecular Biology
Gene
Phylogeny
Ecology, Evolution, Behavior and Systematics
Gene Rearrangement
Base Sequence
Phylogenetic tree
Nucleic acid sequence
Chromosome Mapping
Sequence Analysis, DNA
Gene rearrangement
Chlorurus sordidus
biology.organism_classification
Perciformes
Transfer RNA
Sequence Alignment
Pseudogenes
Subjects
Details
- ISSN :
- 14321432 and 00222844
- Volume :
- 59
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Evolution
- Accession number :
- edsair.doi.dedup.....f6eb783f47cac82d99932a74ef52f8b3