Type of Document	Thesis
Author	McGhee, Katie E
URN	etd-09182003-144532
Title	The Roles Of Allorecognition And Larval Interactions In The Fusion Of Swimming Sponge Larvae
Degree	Master of Science
Department	Biological Science, Department of
Advisory Committee	Advisor Name Title Don Levitan Committee Chair Alice Winn Committee Member Joe Travis Committee Member
Keywords	Recognition System Larval Fusion
Date of Defense	2003-08-02
Availability	unrestricted
Abstract For sedentary marine invertebrates, allorecognition systems allow individuals to distinguish between genetically similar and distinct tissue they may encounter and are thought to reduce costly tissue fusion with individuals other than self or kin. In this study, I examined the effects of relatedness on the fusion frequencies of the purple sponge, Haliclona sp., as sedentary adults and as free-swimming larvae. While adult sponges fuse preferentially with related tissue; larvae fuse equally with sibling and non-sibling larvae at an average rate of 13.4% resulting in swimming larval chimeras capable of successful metamorphosis. In contrast to the adult fusion pattern, these results suggest that larvae are unable to distinguish between individuals of varying relatedness. Although the effect of relatedness on larval fusion rate was non-significant, adult sponges differed significantly in the propensity of their larvae to fuse, with some adult sponges producing larvae that are more fusible than those produced by others. Analysis of larval swimming behavior indicates that larvae aggregate and are capable of increasing the probability of encountering other larvae. The pursuit of fusion at this motile stage along with the evidence of a functioning adult allorecognition system, suggests that larvae may not express a recognition system, or that factors other than relatedness, such as potential benefits to larval or adult chimeras, may be involved in larval fusion and a stageactivated allorecognition system.
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