Do the specific genes chosen to be expressed through epigenetics, due to environmental and lifestyle factors, affect the transfer of genes during sexual reproduction?
In laymen's terms, if I'm born with genes that favor a skinny body type, but for my entire life eat in such a way that for years before I reproduced I was morbidly obese, which would create negative epigenetic trends toward fat storage capacity, would that tendency toward the expression of fat retention genes rather than genes favoring a more slender body type be passed down to my children?
The inverse of my question would also be true, would a person born with a high chance of diabetes but who ate a low carbohydrate diet their whole life and never saw the expression of his diabetic genes have children with a lower chance of acquiring those genes?
My question stems from the fact that it is well established in the medical field that epigenetic influences can change the expression of certain genes, but can those changes be passed down to the next generation?
In laymen's terms, if I'm born with genes that favor a skinny body type, but for my entire life eat in such a way that for years before I reproduced I was morbidly obese, which would create negative epigenetic trends toward fat storage capacity, would that tendency toward the expression of fat retention genes rather than genes favoring a more slender body type be passed down to my children?
The inverse of my question would also be true, would a person born with a high chance of diabetes but who ate a low carbohydrate diet their whole life and never saw the expression of his diabetic genes have children with a lower chance of acquiring those genes?
My question stems from the fact that it is well established in the medical field that epigenetic influences can change the expression of certain genes, but can those changes be passed down to the next generation?
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Yes, but...
1. Epigenetic changes are, by definition, heritable and physical. (That said, what specifically is considered "epigenetics" can sometimes be fluid.)
2. Most epigenetic changes are *not* passed on generation to generation. Most epigenetic changes are *developmental.* The epigenetic state of a fetus is very different from an adult, even though the DNA code is exactly the same. From a functional standpoint, epigenetics is a means of genomewide regulation. [Or think about cancer - we're discovering the epigenetic state of cancer cells are often very different from that of healthy cells.]
3. While epigenetics is affected by the environment, the changes caused by the environment are harder to predict - it's not like selection where you can actually predict what the phenotypic effects will be. In your example, eating more can contribute to obesity. But that doesn't mean that its epigenetic changes contributing to obesity. And even it it were epigenetics, that doesn't mean it's heritable to the next generation, and the epigenetic effects might even be in the other direction (lessening the chance of obesity). We don't know enough about epigenetics yet to predict those effects.
Hope that helps. The main point I would like to emphasize is #2: the pop media (and even a lot of usually good scientific media) coverage of epigenetics has overblown the parent-to-child heritability of epigenetics. Worse, they've been interpreting it from a Lamarkian model. When you're talking about heritability in epigenetics, most of the changes are within an individual's lifetime. Scientists are more interested in studying it from a cancer and development standpoint.
1. Epigenetic changes are, by definition, heritable and physical. (That said, what specifically is considered "epigenetics" can sometimes be fluid.)
2. Most epigenetic changes are *not* passed on generation to generation. Most epigenetic changes are *developmental.* The epigenetic state of a fetus is very different from an adult, even though the DNA code is exactly the same. From a functional standpoint, epigenetics is a means of genomewide regulation. [Or think about cancer - we're discovering the epigenetic state of cancer cells are often very different from that of healthy cells.]
3. While epigenetics is affected by the environment, the changes caused by the environment are harder to predict - it's not like selection where you can actually predict what the phenotypic effects will be. In your example, eating more can contribute to obesity. But that doesn't mean that its epigenetic changes contributing to obesity. And even it it were epigenetics, that doesn't mean it's heritable to the next generation, and the epigenetic effects might even be in the other direction (lessening the chance of obesity). We don't know enough about epigenetics yet to predict those effects.
Hope that helps. The main point I would like to emphasize is #2: the pop media (and even a lot of usually good scientific media) coverage of epigenetics has overblown the parent-to-child heritability of epigenetics. Worse, they've been interpreting it from a Lamarkian model. When you're talking about heritability in epigenetics, most of the changes are within an individual's lifetime. Scientists are more interested in studying it from a cancer and development standpoint.