Type of Document	Thesis
Author	Fuller, Rebecca C
URN	etd-08312003-234623
Title	The Evolution Of Color Patterns And Color Vision In The Bluefin Killfish, LUCANIA GOODEI
Degree	Doctor of Philosophy
Department	Biological Science, Department of
Advisory Committee	Advisor Name Title Joseph Travis Committee Chair David Gruender Committee Member Don Levitan Committee Member Jim Fadool Committee Member William Herrnkind Committee Member
Keywords	Genetics Lighting Environment Heritable Responses To Lighting Environment
Date of Defense	2003-06-01
Availability	unrestricted
Abstract The degree to which signals and sensory systems are heritable has implications for sexual selection. Coevolutionary models predict heritable variation in both signals and sensory systems. Constraint models predict that signals are heritable but that sensory systems are invariant. I test these predictions by examining variation in color patterns and vision physiology in the bluefin killifish, Lucania goodei. Males are polymorphic in anal fin coloration . Anal fins are either solid blue, solid red, solid yellow, a combination of red and blue, or a combination of yellow and blue. Lighting conditions range from crystal, clear springs (high transmission UV/blue wavelengths) to tea-stained swamps (low transmission UV/blue wavelengths). In a census study, blue morphs were more common in populations with low transmission of UV/blue. Red and yellow morphs were more common in populations with high transmission of UV/blue. A genetics study revealed that a simple epistatic interaction accounts for the majority of variation in color patterns. Red-versus-yellow is controlled by a single locus to which blue expression is orthogonal. Males are more likely to express blue when raised in tea-stained water. There is heritable variation in the propensity of males to express blue as well as in their response to the environment. Across populations, vision physiology covaries with lighting conditions. Electroretinogram readings indicated that swamp animals were less sensitive to UV/blue than spring animals. Microspectrophotometry data suggested that UV and violet cones were more abundant and that yellow and red cones were less abundant in spring animals as compared to swamp animals. To examine variation within populations, I used realtime PCR to measure the expression of opsin genes that determine cone sensitivity. In a breeding experiment, I found both genetic and environmental variation in relative opsin expression. Yellow opsin varied significantly across sires, and violet opsin varied significantly across dams. Both ultravioet and violet opsin expression was higher for animals from clear-water, whereas yellow and red opsin expression was higher for animals from tea-stained water. Thus, sensory systems are dynamic, readily evolvable traits in contrast to the invariant systems assumed by the constraint models of sexual selection.
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