this post was submitted on 16 May 2024
93 points (93.5% liked)
Asklemmy
44003 readers
356 users here now
A loosely moderated place to ask open-ended questions
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- [email protected]: a community for finding communities
~Icon~ ~by~ ~@Double_[email protected]~
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
The current paradigm assumes a uniform probability of mutation across all genes. But maybe there are mechanisms that say “keep this part of the genome under tighter control” and “make this other part of the genome more susceptible to mutation.”
Oh we already know this. There are parts of the genome that, if even slightly changed, cause terrible, terrible things.
Mutations can happen anywhere, but serious mutations (that may affect the basic things a cell needs to do in order to exist) result in cell death and therefore don’t manifest in the population — the population continues on as though the mutation had never existed.
In this way, natural selection conserves some parts of the genome while less essential parts can vary more freely without being deleterious to the organism.
For example, most non-bacteria (including all plants, animals, fungi, protists) have special proteins called histones. Histones are used to package the DNA together and wrap it all up. Cells can’t function at all without a these proteins, and the most important histone proteins evolve so slowly that they’re almost identical between a human and a pea. (Humans and peas shared a common ancestor over half a billion years ago.)
ETA: My molecular biology knowledge is rusty, but IIRC the way DNA is packaged and unpackaged can also reduce or increase the risk of DNA being exposed to potential mutagens. So if it’s wrapped up, it’s harder to access and tamper with