You are here:
Use of gene expression data to determine effects on gonad phenotype in Japanese medaka after exposure to trenbolone or estradiol
Citation:
Flynn, K., J. Swintek, AND R. Johnson. Use of gene expression data to determine effects on gonad phenotype in Japanese medaka after exposure to trenbolone or estradiol. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 32(6):1344-1353, (2013).
Impact/Purpose:
The goal of the current work was 2-fold. The first was to produce, via exposure to 17β-estradiol, XY medaka with gonads of mixed phenotypes. Then data from both 17β-estradiol and 17β-trenbolone exposures that produced XX ovaries, XY testes, XX testes, XY ovaries, and XY intersex gonads could be analyzed. The second important goal was to advance the statistical techniques from using PCA as a heuristic tool that allows for the graphical analysis of the total dataset to a more appropriate tool that is able to determine whether statistical differences exist between treatment groups. A permutational MANOVA approach has the ability to do just that, thus extending our gene expression dataset from a molecular description of phenotype to a tool that can be used to quantitatively determine the dose-dependent effects of EDCs on gonad phenotype as measured via gene expression, reaching similar conclusions as a histological analysis of phenotype without the associated inefficiencies and uncertainties.
Description:
Various aquatic bioassays using one of several fish species have been developed or are in the process of being developed by organizations like the US Environmental Protection Agency and the Office of Economic Cooperation and Development for testing potential endocrine disrupting chemicals. Often these involve assessment of the gonad phenotype of individuals as a key endpoint that is inputted into a risk or hazard assessment. Typically, gonad phenotype is determined histologically, which involves specialized and time consuming techniques. The methods detailed here utilize an entirely different methodology, reverse transcription quantitative PCR, to determine the relative expression levels of four genes and by extension, the effects of endocrine disrupting chemicals on the phenotypic status of the gonad. The four genes quantified are all involved in gonad development/maintenance in Japanese medaka (Oryzias latipes); this data is then inputted into a permutational MANOVA to determine whether significant differences exist between treatment groups. This information in conjunction with the sexual genotype, which can be determined in medaka, can be used to determine adverse effects of exposure to EDCs in a similar fashion to the histologically determined gonad phenotype.
URLs/Downloads:
PREDICTION_OF_GONAD_PHENOTYPE_IN_MEDAKA_USING_EXPRESSION_DATA_FROM_FOUR_GONADAL_GENES_STICS[1].DOCXhttp://onlinelibrary.wiley.com/doi/10.1002/etc.2186/abstract
