The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholars Program

GVSP Summer 2009 Scholars

Georgia Veterinary Scholar

Faculty Mentor

Kate Holmberg
University of Georgia
Class of 2012

Dr. Richard Winn
Fish Biotechnology

UGA Warnell School of Forestry & Natural Resources

Assessment of mutations induced in male germ cells by Benzo[a]pyrene

* K. Holmberg under the direction of R. Winn

Environmental exposure to pollutants poses risks for developing cancer and genetic diseases. Benzo[a]pyrene (BaP) is a ubiquitous environmental pollutant that is a byproduct of incomplete combustion of organic matter and is known to be carcinogenic and mutagenic to somatic cells. However, it has not been determined whether BaP can induce mutations in male reproductive cells, and if analyses using isolated spermatozoa may serve as a practical and sensitive surrogate to progeny. To investigate whether mutations were present, 4 groups of 15 lambda transgenic medaka fish carrying the cII target gene were exposed to BaP for six hours per day, for two days, at four exposure levels: 0, 250, 500, and 1000 ppb BaP. To evaluate the responsive germ cell stage, spermatozoa were collected at two different time intervals, 15 days post exposure and 30 days post exposure to test the post-meiotic and pre-meiotic spermatozoa, respectively. The cII gene was recovered and the mutant frequency (MF) was determined using the cII assay. Preliminary analyses show the frequencies of mutant cII genes in spermatozoa from exposed males were not significantly elevated compared to controls. Although the negative responses were unexpected, these results may reflect the greater potential of reproductive cells to either protect themselves from mutations or eliminate mutant spermatozoa. Ongoing studies will analyze progeny for mutations and will use a higher dose of BaP to investigate if male germ cells are protected from the effects of this mutagen.