Epigenetics Study

This study is investigating how environmental exposures might change how the body interprets its genes. These changes, known as epigenetic effects, can in turn influence health. The study is being conducted among CHAMACOS Cohort participants.

Epigenetic Mechanisms (Reprinted by permission from Macmillan Publishers Ltd: Nature 441: 143-145. 11 May 2006.)

 

What are Epigenetic Effects?

The Epigenetics Study Investigates:

  • We aim to identify specific regions of the DNA sequence where epigenetic modifications can be used as biological markers (“biomarkers”) of environmental exposure or child development or health.
  • We are using the rich collection of biological samples, pesticide and other environmental exposure information, and health and developmental outcome data collected by the CHAMACOS Study from Cohort participants.
  • This study will provide some of the first data on epigenetic changes in children and their association with environmental exposures and developmental outcomes.

Study Participants and Data Collection:

Assays for Site-specific and Global DNA Methylation, including:

  1. Illumina Infinium Methylation 450k assay.  This is a bead array assay that allows us to examine over 450,000 highly informative CpG (methylation) sites per sample.
  2. Alu and LINE-1 repeats pyrosequencing.  Alu and LINE-1 repetitive DNA sequence elements are very common patterns within the human genome.  Methylation status of these repeated sequences can be used as a marker of global (overall) methylation status.

What Are Epigenetic Effects?

Epigenetic effects (individually called epigenetic markers) are reversible, heritable changes to the way the body interprets and expresses its genetic code (DNA). Epigenetic effects occur without changing the DNA sequence (i.e., without changing genotype).

DNA Methylation:

DNA methylation is an example of an epigenetic marker. It is also currently the most well-recognized epigenetic marker. DNA methylation occurs when a methyl group becomes fixed to a particular segment of DNA (see top of image to the right). The presence of the methyl group changes the way the body reads the particular DNA sequence. Usually, methylation in a particular section of DNA effectively “turns off” that gene, leading to lower gene expression.

Epigenetic effects like DNA methylation can have varied implications for one’s health, as the outcome will depend on what the methylated DNA originally coded for.

About Epigenetic Effects:

  • Epigenetic effects are heritable changes in phenotype, or gene expression, in the absence of changes in the base pairs of the DNA sequence, or genotype. (The word phenotype describes all observable characteristics or traits of an organism that arise as a consequence of the interaction of its genotype and the environment, including everything from eye color to health.)
  • DNA methylation, the most common type of epigenetic marker, is known to play an important role in cancer, aging, neurodevelopment, and fertility.
  • Recent research has shown that changes in widespread DNA methylation in blood DNA have been associated with environmental exposures, including exposure to persistent organic pollutants, benzene, and air pollution.
  • Little is known about the occurrence of DNA methylation in children, including what variations occur with sex or age, and possible associations with health endpoints or environmental exposures.
  • Epigenetic markers may be a key mechanism by which environmental exposures affect health during childhood, as well as in later life and future generations, according to the hypothesis of the fetal origin of human disease.

Research Team:

  • Nina Holland, PhD
  • Brenda Eskenazi, PhD
  • Karen Huen Northcote, PhD
  • Vitaly Volberg, MPH
  • Paul Yousefi, MPH
  • Raul Aguilar Schall, PhD
  • Subha Venkat, PhD
  • Lisa Barcellos, PhD
  • Asa Bradman, PhD
  • Kim Harley, PhD

 

This study is just beginning (2011).
Check back for updates on our progress and findings.

Funded by: Duration: Study Contact:
The National Institute for Environmental  Health Sciences (NIEHS) and U.S. Environmental Protection Agency (EPA) 2010-2014, ongoing
Nina Holland, PhD Director Children’s Environmental Health Laboratory and
Project Director, PON1 Study
ninah@berkeley.edu
510-665-2200
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