Date of Award


Document Type

Open Access Thesis


Biological Sciences

First Advisor

Jeffry L. Dudycha


The serine protease (SP) gene family is an ecologically important gene family because of observed involvement in innate immunity, digestive processes, and embryological development of arthropods. In the past decade, all genes of the serine protease family have been classified in a number of arthropods, with the exception of crustacean. Possible evolutionary mechanisms have been observed based off of varying selectional pressures acting on recent SP expansions in respect to varying diets. Daphnia is the first crustacean to have its genome sequenced, and their genomes were analyzed in this study to elucidate the expansion and divergence of the SP gene family across arthropods in respect to similar diet. In this study, all SP-like genes were extracted from the D. pulex and D. magna genomes. Multiple bioinformatic approaches were used to catalogue the structural and biochemical properties of functional serine proteases in both Daphnia genomes. Phylogenetic analysis and selection tests, within and between both species of Daphnia, showed purifying selection reinforced the role of basal digestive proteases within Daphnia before and after divergence in respect to similar diet preferences.

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Biology Commons