Scott Baird (Advisor), Dan Krane (Committee Member), John Stireman (Committee Member)
Master of Science (MS)
Assortative fertilization refers to the species-specific interactions between sperm and oocytes that affect the success of fertilization. One type of interaction is chemotaxis of sperm to oocytes. In Caenorhabditis elegans, amoeboid sperm must crawl along the uterine lining towards the spermathecae in response to oocyte-derived prostaglandin signals for fertilization. This chemotactic signaling system likely operates in other species of the Elegans-Group of Caenorhabditis as sperm of C. briggsae and C. remanei do localize to the C. elegans spermathecae. In this project the impacts of species-specific chemotaxis on fertilization and female fecundity were assessed. To accomplish this, the localization of fluorescently-labeled C. remanei sperm to the spermathecae was determined in C. nigoni, C. briggsae, and various C. nigoni: C. briggsae hybrid `females'. Each of these crosses was also scored for cross-fertility and cross-fecundity. These data were used to study correlations between sperm chemotaxis, cross-fertility and cross-fecundity. Variation in sperm chemotaxis explained only 1% of the variation in cross-fertility and only 8% of the variation in cross-fecundity. Additionally, sperm-derived chemotactic signaling for oocyte maturation and ovulation do not appear to be species-specific. Therefore, other mechanisms, such as specific-specific receptor-ligand interactions and/or insemination reactions, must also contribute to assortative fertilization in Caenorhabditis.
Department or Program
Department of Biological Sciences
Year Degree Awarded
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