Research

Germ Cell Development

We are studying epigenetic regulation of germ cell development in medaka gonads by using vasa-gfp medaka as a model. Sex differences in germ cells are believed to be epigenetically regulated, as distinct differences in DNA methylation and histone modifications have been found in germ cells during sex determination. We dissect epigenetic landscape of germ cells at various stages of development.


Brain Sex Differences

One of our interests is to understand brain sexual dimorphism and environmentally inducible sex specific behaviors. Using Cyp19a1b-GFP medaka, we dissect basic epigenetic landscape of radial glial cells in the brain and study epigenetic and transcriptional alterations in these cells caused by environmental stressors.


Transgenerational Inheritance of Environmentally Induced Health Effects

The window of early embryonic development is susceptible to environmental chemical stressors. Exposures during gonadal sex determination may lead to reproductive defects in the exposed individuals. These effects can be transmitted to subsequent generations via germ line (sperm and eggs).  Some effects can be transgenerationally transmitted to offspring across several generations. Transgenerational effects are those effects that appear in individuals not because of direct exposure but due to ancestral exposure. Transgenerational phenotypes have been thought to be contributing to declining reproductive fitness and emergence of endangered situation of a species in a natural popuation. In order to provide insights into these critical issues, we are studying molecular alterations occuring during transgenerational inhertitance of phenotypes to identify chemcial and phenotype specific biomarkers associated with adverse reproductive outcomes using medaka fish (d-rR medaka, Oryzias latipes) as a model. We anticipate these biomarkers to be reliably predictive of history of exposure and associated transgenerational phenotypes.


Environmentally induced epigenetic memory

Gene-environment interactions can lead to emergence of a phenotype. Environmental stressors are able to induce changes at the epigenetic level (chemical modifications on DNA structure) that are mitotically (and may be meiotically) stable. Our research is focused on unraveling of epigenetic memories established by a variety of environmental stressors that humans are exposed to in thier everyday life. We take in vitro cell culture, in vivo animal models, nextgen high throughout RNA/miRNA/epigenome sequencing, and bioinformatic approaches to dissect molecular underpinning of environmentally induced health effects across generations using an aquarium fish as a model. We anticipate finding permanent epigenetic memories that interfere with fine-tuned transcriptional wiring leading to abnormal behavior of a gene (or genes).


Epigenetic effects of early developmental exposure to emerging environmental contaminants.

Hundreds of chemicals are being introduced into the market and their effects on ecosystem and human health are not clearly understood. Our research suggests that developmentally established epigenetic changes can survive in the body throughout the lifetime of the exposed individual. We, therefore, are interested in examining epigenetic effects of emerging contaminants of environmental concern in developing organisms. Findings from our study will provide insights into possible long-term health effects of developmental exposure to such chemicals.