Dr. Michael Skinner lays down how environment exposures can impact epigenetics and generations to come. This short take was shot during a break at Keystone Symposia’s meeting on Environmental Epigenomics and Disease Susceptibility held in March 2011 in Asheville, North Carolina.
Epigenetics and Transgenerational Inheritance
I’ve been a researcher in the area of reproductive biology for probably over 20 years, and we kind of stumbled into this epigenetics field about ten years ago, and my research – I’m a basic research scientist, we do reproductive biology and now environmental epigenetics; is sort of the research area we work on.
As I mentioned, I’m a professor in biological sciences, and so we like to take a more basic approach in terms of how our research fits into the overall biological system, and what we’re interested in is how right now basic reproductive processing or development occurs in both the testes and ovary, and then how environmental factors affect that.
What that does now, that we’ve found, is induce epigenetic changes which then can have not only effects on the individual exposed, but essentially get programmed so that all subsequent generations to come will have a shift in either their disease states or phenotypes.
So what we’ve found is the current paradigm for disease and health in general is the genetics, actually, the basic DNA sequence determines pretty much all of biology. For disease, what the thought is that the basic mutations in that sequence – or changes in the genetics – is the causal factor for disease.
The problem with that paradigm – and that’s called “genetic determinism” – the problem with that paradigm is that very few genetic abnormalities have been shown to be associated with disease: actually, just a very small percentage of almost any disease is sort of genetically-based.
Yet we’ve also known that environment has a significant impact on the induction of disease in terms of where disease develops. So because of those two sort of problems – the lack of genetic mutations and this environmental factor – that really can’t change the DNA sequence, but we know it correlates with the disease.
“Our research has actually demonstrated that environmental exposures, particularly compounds – toxicants in the environment, environmental toxicants sort of endocrine disruptors sort of things – can actually induce disease through changing the epigenetics or epigenome of the individual cell…”
Our research has actually demonstrated that environmental exposures, particularly compounds – toxicants in the environment, environmental toxicants sort of endocrine disruptors sort of things – can actually induce disease through changing the epigenetics or epigenome of the individual cell types, or the individual, could then later in life cause the adult onset disease.
So this provides the mechanism – epigenetics provides the mechanism on how an environmental factor can actually epigenetically change the cell, no mutations in DNA sequence, but change the epigenome, which then causes this later life disease.
So essentially this area provides pretty much the basic molecular mechanism on how disease develops, cooperates with the genetics, but provides much further insight than previously appreciated.
So our research actually addresses that basic element, and not only in the individual exposed, but how in the germ line it gets transferred to subsequent generations as well.
Keystone Symposia’s meeting on Environmental Epigenomics and Disease Susceptibility
It’s a very delightful meeting, and the surprising thing is there’s such a large group of people now interested in environmental epigenetics: how environment can impact disease through epigenetics. Ten years ago basically the numbers would be only in a few dozen people, and so now we have hundreds of people sort of interested, showing that the field of epigenetics – and particularly environmental epigenetics – is really exploding over the past year or two.
So having this meeting really does bring to heart that there’s lots of people and a growing interest in this area. Since it’s such a basic molecular mechanism for disease, this type of conference is very unique right now; I suspect they’ll become more common in the future. But it’s very nice to see the main players and then the students and so forth coming up that are really going to fill that field in the future.
I have talked at a large number of Keystone meetings over the past couple years, but this is the first one that I’ve seen focused only on epigenetics, which is very nice; the other ones were more biological or disease-oriented sort of meetings, and so this is that.
One of the main areas that I’ve sort of helped initiate is this area called “epigenetic transgenerational inheritance.” So what that means is an environmentally induced epigenetic change creates an affect in the sperm or the egg?
What that means is it’s not only the individual exposed, but the progeny of that individual has an altered epigenome and can develop disease. And if it’s permanently programmed, it will occur not only in the next progeny, but all subsequent progenies to come in generations to come. It’s a permanent shift transgenerationally.
So the reason that’s important is for disease states it could be that we’re seeing this increase in disease state in the human population based on this continual increase in transgenerational epigenetics. So basically now 35 percent of North Americans have obesity because there’s this increasing sort of generational affect that has impacts on how we think about how disease develops, but it also has significant impacts in areas such evolutionary biology.
This can explain how an organism can get exposed to an environmental factor, affect the germ line, and then all subsequent generations to come will have a shift in the phenotype. Well, if the whole population gets exposed, it explains how this evolutionary event occurred in this population, and then somewhere else in the world how it shifted a different way based on the environment.
So this area of environmental epigenetics really impacts pretty much all of biology. So I’m here because that sort of area is really rapidly growing, and the basic mechanisms of that is what we’re interested in.
First of all, environmental epigenetics is really going to be at the heart of a large number of areas: everything from disease etiology – how disease develops – to evolutionary biology in terms of the basic mechanisms. So I think the future will be actually to broaden this area of epigenetics, to consider pretty much all areas of biology. What’s happening is, the current paradigm that genetics and genetic determinism is the primary factor, really is true that it’s very important, but now it’s understood that epigenetics is probably equally important as a regulatory step, from everything from evolution down to disease.
So, really, I think the future will actually be incorporating environmental epigenetics into nearly every area of biology, from health to sort of evolution. I think that’s what we’re going to see over the next decade or so.