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Defended and Graduated
February 2003
Thesis: Nuclear
Intron Phylogenies and Evolution of Clonality Among Northeastern
Pacific Anthopleura Speices
Abstract:
Four species of Anthopleura are found in the northeast Pacific:A.
xanthogrammica,
A. artemisia, A. elegantissima, and A. sola. Life
histories vary in these species, with A. elegantissima being
clonal 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 the direction of life history change, nuclear introns
of a G-protein coupled receptor (GPCR) gene (~250 bp) and an arginine
kinase (AK) gene (~570 bp) were sequenced. We obtained 57 GPCR sequences
from 29 individuals and 149 AK sequences from 53 individuals. New and
prior evidence suggests that A. artemisia is distantly related
to the other three northeastern Pacific species, and it was therefore
used
as an outgroup. Maximum parsimony reconstructed clades dominated by
A. elegantissima and A. sola as sister taxa, with A.
xanthogrammica
branching from a basal position. 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. Accepting A. sola and A. elegantissima as
sister species and A. xanthogrammica as basal, we conclude that
clonality is a recently derived trait in A. elegantissima.
Current Employment:
Lab Technician in the Biochemistry Department at the University of New Hampshire (UNH).
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