극피동물, 둥근성게과 성게들의 속 수준 분류 논쟁에 대한 해결

Abstract

Sea urchins of the family Strongylocentrotide have been one of the most important model organisms in marine biology, yet our understanding on their evolutionary history remains limited. Genus-level classification of this family still contain a controversy: the phylogenetic locations of the genera Hemicentrotus, Pseudocentrotus and Loxechinus have been unresolved. Here, we have constructed a molecular phylogeny for the species of Strongylocentrotidae including a few other sea urchin species (Strongylocentrotus franciscanus, S. nudus, S. purpuratus, S. intermedius, S. droebachiensis, Hemicentrotus pulcherrimus, Pseudocentrotus depresssus, Anthocidaris crassispina, Loxechinus albus, Sterechinus neumayeri and Pseudechinus. magellanicus) using nucleotide sequence data from 12SrDNA-tRNA(gln) region (862 nt) and cytochrome oxidase subunit I (COI, 1080 nt). The phylogentic relationshiop among the species analysed by the methods of ML, ME, MP in the PAUP* program is summarized by (((((((S. intermedius, S. droebachiensis) S. purpuratus) H. pulcherrimus), ((S. nudus, S. franciscanus) P. depressus))) A. crassispina), ((L. albus, S. neumayeri) P. lividus))) P. magellanicus). Four species of the genus Strongylocentrotus (S. intermedius, S. droebachiensis, S. nudus and S. franciscanus), H. pulcherrimus and P. depresssus make a closely related clade, indicating their belonging to the family Strongylocentrotidae. On the other hand, L. albus and A. crassispina are distinctively separated from this clade, suggesting their belonging to other families. These foundings based on the molecular phylogeny provide a resolution for the long-lasting controversy on the phylogenetic positions of the genera, Hemicentrotus, Pseudocentrotus, and Loxechinus.