Environment specific adaptation of antiviral genes in threespine stickleback fish

Date of Award

Spring 5-28-2016

Document Type

Honors Project

University Scholars Director

Dr. Jeff Keuss

First Advisor/Committee Member

Dr. Charlotte Pratt

Second Advisor/Committee Member

Dr. Catherine Peichel


stickleback, antiviral, Mx, evolution, adaptation


The threespine stickleback fish (Gasterosteus aculeatus) is a diverse teleost species inhabiting both marine and freshwater environments in the Northern Hemisphere following divergence events 15,000 years ago. Inhabiting either freshwater or marine niches dictates the behavioral and morphological diversity between stickleback populations. Known suites of external factors, such as predators and water conditions, drive this variation in environments. Similarly, the presence of different viruses could increase selective pressure on host antiviral proteins depending upon the environment. We searched stickleback antiviral genes for evidence of selective pressure at the nucleotide and protein sequence levels. From an initial list of 104 stickleback gene transcripts, ten transcripts appear to be under positive selection. Specifically Myxovirus resistance protein (MxA) and Protein Kinase R (PKR) were chosen for further analysis. Analysis of freshwater and marine sequences reveals amino acid residues that segregate between freshwater and marine ecotypes. Many of these residues are completely fixed between ecotypes. We suggest that the alterations found in stickleback antiviral genes are lineage-independent and environmentally-determined. Encounters with different viruses or viral pressures may lead to divergence between the marine and freshwater ecotypes.


A project submitted in partial fulfillment of the requirements of the University Scholars Program

This document is currently not available here.


Copyright Status

Additional Rights Information
Copyright held by author.