Master of Science (M.S.)
Moss Landing Marine Laboratories
Four species of Anthopleura are described for the northeast Pacific: A. xanthogrammica, A. artemisia, A. elegantissima and A. sola. Life histories vary in these species, with A. elegantissima a clonal species and the others solitary. Unusually slow rates of mitochondrial DNA evolution in anthozoans necessitate the use of quickly evolving nuclear genes for evolutionary studies of closely related species. To reconstruct phylogenetic relationships and determine evolution of clonality within this group, nuclear introns of a G-protein coupled receptor (GPCR) gene (~250 bp) and an arginine kinase (AK) gene (~570 bp) have been sequenced. I obtained 57 GPCR sequences from 29 individuals and 149 AK sequences from 53 individuals. Sequence analysis suggests A. artemisia is distantly related to the other three northeastern Pacific species, and was therefore used as an outgroup. Maximum parsimony reconstructs clades dominated by A. elegantissima and A. sola as sister taxa, with A. xanthogrammica branching from a basal position. By parsimony, clonality is a derived character state in A. elegantissima. The gene genealogies, however, do not show reciprocal monophyly of species. These results suggest that lineage sorting of ancestral polymorphisms, following a recent speciation, is incomplete.
Fitzgerald, Laurie J., "Nuclear intron phylogenies and evolution of clonality among Northeastern Pacific Anthopleura species" (2003). Capstone Projects and Master's Theses. 127.