The University of Georgia College of Veterinary Medicine

eorgia Veterinary Scholars Program

GVSP Summer 2007 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Tamara Powell University of Georgia Class of 2010	Dr. Richard Winn

Untargeted Mutagenesis in the Medaka

Tammy Powell*, under the direction of Dr. Richard Winn
Aquatic Biotechnology and Environmental Lab (ABEL)
2580 Devil's Ford Road, Warnell School of Forestry and Natural Resources
University of Georgia, Athens, Georgia 30602, USA

Abstract

Untargeted mutagenesis research has indicated that genetic mutations can not only be inherited from parent to child, but can also be induced. Exposure to mutagens like cigarette smoke, chemotherapy agents, or environmental contaminants may have a delayed effect on the offspring of the person who was exposed. Therefore, individuals exposed to a strong mutagen may have offspring that are at an increased risk of developing a genetic disease. The health risks of this type of mutagenesis need to be studied, and a functional animal model is needed. Our lab uses the medaka, a small Japanese minnow commonly used for toxicology and genetics research. We exposed the male medaka to the powerful mutagen ethylnitrosourea. The females were not exposed. The females had a transgene called lambda cII in their genome that was passed on to offspring and served as a target for extraction and mutation analysis. A high mutational frequency in this gene indicates that mutations were induced in the offspring, since the gene was inherited solely from unexposed females. The father’s damaged DNA probably induced the mutations. Our hypothesis is that we will see a significant number of mutations in the cII gene of the offspring of ethylnitrosourea-exposed fathers. We have begun to evaluate this hypothesis by extracting DNA from the offspring for analysis in a cII assay, in which the DNA will be packaged into bacteriophage particles. The packaged phages, along with E. coli G1250 cells, will be plated onto TB-1 agar plates. The plates will be incubated in conditions that allow the growth of phages with mutant cII but not of phages with wild-type cII. Our goal is to support the medaka’s use as an animal model for untargeted mutagenesis research, and to encourage further studies into untargeted mutagenesis.