Event Highlight: Genetics and Epigenetics - Beyond Nature vs. Nurture

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On Tuesday, December 11th, the Sustainable Path Foundation hosted a lively forum about epigenetics at Town Hall Seattle. The speakers were Dr. Michael Skinner and CEEH Investigator Dr. Kelly Edwards

Dr. Skinner directs a lab at Washington State University's Center for Reproductive Biology. His research is focused on investigating how different cell types communicate to regulate gonadal growth and differentiation. Work in his lab with rats has demonstrated that endocrine disrupting chemicals promote transgenerational epigenetic disease phenotypes through abnormal germ line programming during development of the gonads. 

Dr. Kelly Edwards is Associate Professor in the UW Dept of Bioethics and Humanities and core faculty in the Institute for Public Health Genetics. She is Co-Director of the Regulatory Support and Bioethics Core for the Institute for Translational Health Sciences and Director of this Center's Community Outreach and Ethics Core (COEC). Her research interests include integrating ethics into training programs, public conversations about science and public policy, ethics in research practice, and environmental justice. 

Dr. Skinner explained that DNA methylation and histone modification regulate gene expression. The methylation doesn't change the sequence of base pairs, but it does control how the genes work. The surprise is that methylation patterns are inherited. You inherited yours from your great-grandparents. Your maternal grandmother's dietary and chemical exposures when she was pregnant with your mother also exposed your mother and your mother's germ cells. Now here's the inheritance bit - you will pass the effect of what your grandmother was exposed to, to your children. Your grandmother's exposures influenced the methylation pattern of your DNA, and you pass that to the next generation. Dr. Skinner said something I had not heard before, that our epigenetics are determined from birth.

Dr. Edwards discussed the ethical challenges of epigenetics. She voiced concern that mothers and grandmothers will be blamed for exposures over which they had little or no control. Should women be held responsible for breathing the polluted air in their neighborhood, or using everyday plastics made with endocrine-disrupting BPA and phthalates? Dr. Edwards also suggested epigenetic research in humans will be challenging because it will require generous information sharing, lots of time from participants, and trust between participants and scientists.

The audience had lots of questions. If our epigenetics are determined from birth, is there anything we can do about the health risks we inherited? Or are epigenetics just another reason to give up on taking care of ourselves? Dr. Skinner emphasized that the epigenome - and the genome - we're born with only predisposes us to certain diseases. When the information in individual genomes and epigenomes can be analyzed and understood, medicine will have a powerful new tool for prevention. For example, those who are predisposed to certain diseases could be given preventive drugs and be advised to eat or to avoid certain foods.

Dr. Skinner commented that when he talks to audiences of geneticists, they always try to find a way for  genetics rather than epigenetics to explain his research findings.

On the bus ride home, I picked up the UW Alumni Magazine, Columns. I was surprised to find an article on DNA regulation - "Smart Junk. 'Stam Lab' Leads the Way in Solving DNA Puzzle." Center member Dr. John Stamatoyannopoulos, a researcher in Genome Sciences, is working with colleagues around the country on the Encyclopedia of DNA Elements (ENCODE), a federally-funded project to identify all the functional elements in the human genome. The article stated that what used to be called "junk DNA" contains DNA switches, instructions that switch genes on and off. The ENCODE project will help decipher gene-control pathways involved in disease. Someday soon doctors will be able to diagnose and treat cancer patients based on the cancer's genome.

So is DNA regulated by genetics or epigenetics? What if it's regulated by both? Something else was put forth at the forum: Science is a process of discovery. Scientists have to be open to making discoveries they didn't expect, discoveries that don't fit with their world view. To find the truth, we have to be open to new paradigms.

Event Highlight: Childhood Obesity and The Environment

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On Nov 29th, a panel of 7 experts led by National Institute of Environmental Health Sciences (NIEHS) Director Linda Birnbaum participated the first NIEHS virtual forum. The format was Q&A; participants submitted questions by email, Web, and Twitter. The topic was Child Obesity & the Environment.

Although body size is driven by energy balance, meaning nutrition and physical activity,  environmental exposures also seem to be a factor in the obesity epidemic, particularly at sensitive periods of development such as the prenatal period and early childhood. In obesity, adipocyte or fat cells seems to lose their normal controls. Obese people have more or larger fat cells.

Chemical exposures that have been associated with obesity include:
  • Maternal smoking during pregnancy
  • Phthalates
  • Bisphenol A (BPA)
  • Organotins, used as stabilizers for PolyVinylChloride (PCV)
  • Some pesticides
  • Air pollution from diesel fumes (PAHs) 
  • Indoor dust, especially for young children
Obesity puts people at greater risk for heart disease, stroke, Type 2 Diabetes and some types of cancer. Early exposures are associated with health outcomes later in life: Being undernourished during development is associated 50-60 years later with increased cancer, diabetes, and obesity.

Panelists discussed the food system, which has changed from a generation ago. We eat a different diet prepared in a different way. Portion sizes are larger and even published recipes contain more calories per serving. We make food more palatable - saltier, sweeter, and tastier - which tempts us to overeat.

Trends show some leveling off of obesity rates in the US, although rates are skyrocketing in many developing countries. Our experiences in utero, however, do not predestine us to be obese. There are many choices we can make in life that will help us get fit and stay healthy.