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| Sequence Comparison of Mitochondrial 12S rRNA Genes between Two Crab Species, Macrophthalmid dilatatum and M. japonicus |
| XU Jing-ming |
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Abstract Partial sequences of the mitochondrial 12S rRNA gene were determined for two species crabs, Macrophthalmus dilatatum and M. Japonicus. The results showed that the 12S rRNA gene had 577 bp for M. Dilatatum and 572 bp for M. Japonicus with similar contents of A(39.0 % for M. Dilatatum;39.3 % for M. Japonicus), T(35.7 %, 36.2 %), G(16.5 %,15.8 %)and C(8.8 %,8.7 %). There were 75 different sites(except 11 deletion/insertion sites)between the two species, including 42 transition sites and 33 transversion sites. It was found that the si/sv and ratio of different sites were about 1.3 and 13.18 %, respectively. Furthermore, 331 bp homologous segments were analyzed to discuss the phylogenetic relationship between four Macrophthalmid crabs and other 23 Ocypodoid crabs in the world. The results showed that the average A+T content(76.6 %)was higher than G+C, and there were 52 variable sites and 25 parsimony-information sites in the nucleotides of the four Macrophthalmid crabs data. Neighbor-Joining method revealed that topological structure of the molecular phylogenetic tree constructed by 12S rRNA gene in all species of Macrophthalmid crabs were clustered into one distinct clade, indicating that the monophyly of Macrophthalmid crabs was well supported.
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Received: 25 December 2009
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