Publication Date

2011-05-11

Availability

Open access

Embargo Period

2011-05-11

Degree Name

Master of Science (MS)

Department

Biology (Arts and Sciences)

Date of Defense

2010-11-04

First Committee Member

Athula H. Wikramanayake

Second Committee Member

Barbara A. Whitlock

Third Committee Member

Marguerite A. Butler

Abstract

Megalagrion damselflies have radiated into new breeding habitats independently at least six times in the Hawaiian archipelago, and have evolved bright body coloration numerous times. We hypothesize that these radiations are correlated with specific changes in the opsin proteins. We isolated and characterized two opsin genes from nine different Megalagrion species. The opsin phylogeny is consistent with the phylogeny based on breeding habitat preference of Megalagrion species supporting the correlation between the evolutionary changes of vision and habitat shifts. dN/dS ratios of opsin sequences show that these genes are evolving under purifying selection, though some sites of the opsin genes might be evolving under positive selection. Two terrestrial-breeding Megalagrion species show higher rates of opsin gene evolution that are correlated with a rapid transformation in their breeding habitats from aquatic to terrestrial. These results support the hypothesis that opsin gene evolution has played a role in Megalagrion radiation in Hawaii.

Keywords

Megalagrion, opsin, hawaii, evolution

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