ELI5! What is the difference between genetics, and epigenetics? My experience thus far has been in nature vs. nurture, and epigenetics sounds like it is a grey area in the middle.

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I am studying the effect of trauma on the ability to learn, and I can’t get my head around this concept. I get genetics. I get experience-determined elements, but I do not get epigenetics.

In: Biology
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In many ways, you’re closer to right than you think.

Genetics is your DNA, which I like to describe as a football playbook, here’s how you can do a lot of things, and heres what you should do in response to certain things,. Always.

Epigenetics is the handwritten notes on the margins, and the tabs you use to get to a specific section. When you hand off your ‘genetic playbook’ to your kids, some of the notes go with it, and some of the notes get lost. We don’t understand epigenetics yet, and there’s a lot about genetic regulation we haven’t the foggiest idea about.

Histones, the scrolls that help organize your DNA can be modified to make the section of DNA they contain more accessible, or less accessible. This is handy for turning off/on age related genes, or genes that promote energy use when you’re starving. If it helped you, odds are it might help your kids, so it gets inherited, or gets recreated in them through similar experiences. It’s complicated, and it’s still poorly understood.

I fear I might be oversimplifying too much, but:

* **Genetics** is what’s in your DNA. It’s the actual raw code that says how to make certain proteins and which of those protein-making instructions to actually follow.
* **Epigenetics** refers to heritable, non-DNA circumstances that affect how the code “runs.” The DNA may call for protein XYZ to be made, but due to some (heritable) condition (say, not enough of some nutrient available in utero), that code is skipped or run “incorrectly.” So you end up with a phenotype (i.e. a physical outcome) different from what the genetic code calls for.

Epi means above. It’s a higher level of genetics which affects gene expression without affecting the genetic code itself. Environmental factors during the individual’s lifetime cause chemical modifications to the genetic material. These modifications are basically markers, chemical groups that are stuck onto the chromosome, which have the effect of promoting, demoting, and disabling the reading of that section of the chromosome. This has wide ranging effects on the displayed characteristics of the individual, and epigenetic information carried in the gametes can also be passed on to offspring (i.e. trauma experienced in your lifetime can have an effect on your children).

In the case you’re studying, experienced stress causes cells in the body (brain, perhaps) to add markers to their DNA. These markers mean that some genes are promoted or demoted, and the proteins that are over- or under-produced have critical implications for cognitive function.

Epigenetic information from the parents is ‘nature’ and acquired epigenetic alterations are ‘nurture’.