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Comment by roywiggins | Hacker News Reader

It's worth pointing out that the "genetic changes" in question are changes in gene expression.

Thank you. I have never heard a biologist refer to a change in gene expression as a genetic change. The latter usually refers to a mutation.

And the paper itself makes it clear, it's even in the title- it's the press release that tried to "simplify" it to the point of being confusing.

https://academic.oup.com/endo/advance-article/doi/10.1210/en...

By the article's standard, breathing air produces genetic changes :D

Could you elaborate on that? It doesn't surprise we that "genetic changes" is used sensationally, just would like to know what is actually happening and whether it's uncommon or something pretty normal?

In the simplest terms:

Gene expression constantly changes. It's a field known as epigenetics.

You have tons of genes, not all of which are constantly active.

You have histones in your DNA that allow certain portions to be read while others are locked away. This changes how your genes activate.

Gene expression is not just epigenetics, bacteria also obviously express genes, but largely have no epigenome.

Gene expression changes due to environmental signals, and it happens all the time.

Gene expression >>> epigenetic changes.

Epigenetics is just one of the mechanisms that regulate gene expression in some organisms, but there are many many more mechanisms at play. All cells of a given cell type don't express the same genes at the same level, or even maintain the same expression profile from hour to hour.

Close. But much of the control of gene expression is not formally epigenetic. Much is due to modulation by transcription factors and mRNA splicing machinery. Clearly related to DNA access for transcription but not what is typically meant by epigenetics.

Your DNA is the "cookbook", of what your body can make.

Gene expression is what your body happens to be making (and how much) from the cookbook - and's entirely normal.

I'd have reserved "Genetic changes" for alterations to the cookbook.

Great analogy, thanks!

> Your DNA is the "cookbook", of what your body can make.

> Gene expression is what your body happens to be making (and how much) from the cookbook

Gene expression is what you are making right now, and how much, in a direct and fairly uninformative sense.

But along with recipes for what you can make, your DNA obviously also encodes what you should make, and when, and how much, and how all of that should change in response to various things -- and gene expression is part of that too.

Yep, and this is link to disease that people often miss - when we attribute conditions and diseases to "genetics", what is implied is that it is due to some environmental exposure or detrimental pattern of behavior that hasn't been identified, causing some gene expression/mutation that ends up being harmful.

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