Complete mitochondrial genome of four pheretimoid earthworms (Clitellata: Oligochaeta) and their phylogenetic reconstruction.
Among oligochaetes, the Pheretima complex within the Megascolecidae is a major earthworm group. Recently, however, the systematics of the Pheretima complex based on morphology are challenged by molecular studies. Since little comparative analysis of earthworm complete mitochondrial genomes has been reported yet, we sequenced mitogenomes of four pheretimoid earthworm species to explore their phylogenetic relationships. The general earthworm genomic features are also found in four earthworms: all genes transcribed from the same strand, the same initiation codon ATG for each PCGs, and conserved structures of RNA genes. Interestingly we find an extra potential tRNA-leucine (CUN) in Amynthas longisiphonus. The earthworm mitochondrial ATP8 exhibits the highest evolutionary rate, while the gene CO1 evolves slowest. Phylogenetic analysis based on protein-coding genes (PCGs) strongly supports the monophyly of the Clitellata, Hirudinea, Oligochaeta, Megascolecidae and Pheretima complex. Our analysis, however, reveals non-monophyly within the genara Amynthas and Metaphire. Thus the generic divisions based on morphology in the Pheretima complex should be reconsidered.
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China. Electronic address: sadam@sjtu.edu.cn.
Liangliang
L
Zhang
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
Jibao
J
Jiang
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
Yan
Y
Dong
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China. Electronic address: jpq@sjtu.edu.cn.
Jiangping
J
Qiu
D000818:Animals; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D054629:Genome, Mitochondrial; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009835:Oligochaeta / Q000145:classification* / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial; D012335:RNA, Ribosomal; D012343:RNA, Transfer
Earthworm; Mitochondrial genome; Pheretima complex; Phylogeny