Genetic Basis of Morphological Evolution in Stickleback

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

A grant has been awarded to Dr. LeBlanc (North Carolina State University) to elucidate the basic endocrine control of sexual differentiation in a snail species (mud snail: Ilyanassa obsoleta) and to determine the mechanism by which the biocide tributyltin causes sexual ambiguity in marine snails. Tributyltin is an antifoulant used in marine paints. The material is ubiquitous in the marine environment and has been causally associated with the global occurrence of reproductive system abnormalities in marine snails. Studies will be performed to identify the hormones that are responsible for the development of the snail reproductive system. Initially, field surveys will be performed to establish relationships between hormone or hormone receptor levels and development of the snail reproductive system over the seasonal reproductive cycle. These investigations will be followed by laboratory experiments where levels of tentatively important hormones will be manipulated and consequences to reproductive system development will be established. Once the relevant hormones have been conclusively identified, the effect of tributyltin on those hormone levels and activity will be established. Results from this study will significantly advance our understanding of basic molluscan endocrinology. Many Asian and South American countries are developing snail culture as a sustainable food source for local consumption as well as export. Understanding the regulation of the reproductive cycle of snails would greatly enhance the economic feasibility of such operations. In addition, the International Maritime Organization has implemented a phase-out of tributyltin in marine paints owing to its adverse effects on marine ecosystems. The economic incentive to minimize drag on ocean-going vessels through the use of antifoulants will necessitate the development and use of tributyltin alternatives. Elucidation of the mechanism by which tributyltin interferes with sexual development of snails will help ensure that alternative antifoulants do not share this insidious property.