Thesis
Functional significance of superoxide dismutase (SOD-1): genotypic and phenotypic polymorphism in clonal lines of rainbow trout
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/107026
Abstract
In the past decade a strong correlation has been drawn between an increase of the endogenous antioxidant enzyme superoxide dismutase (SOD-1) activity, the reduction of reactive oxygen species (ROS), and prevention of oxidative damage accumulation which results in increased disease resistance. The variation seen in antioxidant enzyme activity is a major determinant to how susceptible an organism is to ROS attack and oxidative stress (damage done to DNA, proteins, and lipid membranes), yet little is understood concerning the actual genetic controls underlying the degree of phenotypic variation seen. A recent report found that the SOD-1 locus among eight clonal lines of rainbow trout (Oncorhynchus mykiss) is hypervariable, containing 19 SNPs that result in 4 amino acid substitutions. The purpose of this research was to investigate the functional effects of this variation and the genetic basis of variation in SOD-1 enzyme activity. First we compared the SOD-1 enzyme activity in the liver of five of those clonal lines of rainbow trout and found two lines with significantly divergent activities: Oregon State University (OSU) with high enzymatic activity and Arlee (AR) with low enzymatic activity. Next we tested OSU and AR to see if there was a difference in oxidative damage by comparing liver lipid peroxidation (MDA) accumulation in both young (4 month) and old (52 month) individuals. There was no difference in MDA concentrations found between young OSU and young AR, but both older OSU and AR were significantly higher than their younger counterparts, and unexpectedly older OSU had a greater amount of MDA than older AR. Finally, doubled haploid progeny produced from an F1 hybrid of these two lines were used to evaluate the possible quantitative trait loci (QTL) for SOD-1 enzyme activity. Composite interval mapping revealed two significant QTL with opposing additive effects, explaining 19% and 34% of the phenotypic variation; neither of these QTL contain the SOD-1 locus itself. These two QTL, and the surprising inverse relationship between SOD-1 enzyme activity and lipid peroxidation levels, suggest a complex polygenic control for antioxidant activity and oxidative damage accumulation.
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Details
- Title
- Functional significance of superoxide dismutase (SOD-1)
- Creators
- Amber Nicole Parrish
- Contributors
- Patrick A. Carter (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525002601842
- Language
- English
- Resource Type
- Thesis