Thanks. What evidence is there for epigenetic nonrandom adaptive expression, especially passed on from generation to generation? Sorry, I am 23 years out from my undergrad genetics course.
Within a generation, it depends on what you mean. Multicellular life in general requires adaptive nonrandom epigenetic control of expression, since that’s what creates distinct cell and tissue types. (You wouldn’t want eyeballs to suddenly start growing in your liver, for example.) There are also adaptive environmentally triggered epigenetic states, especially in plants, e.g. vernalization.
Adaptive trans-generational epigenetic effects are much more controversial. I don’t follow the subject closely, but I’m not aware of clear evidence for them.
Thank you! I’m learning a lot from these discussions, though I’m not educated enough to field much there. https://en.wikipedia.org/wiki/Transgenerational_epigenetic_inheritance is the Wikipedia note I saw but I don’t trust much to that. @Sy_Garte mentioned something about this on his blog once, too, I think. I appreciate your teaching.
I did mention epigenetics in a post called “Darmarckian Evolution” which was (as the title suggests) a bit tongue in cheek. Dennis Noble has claimed that there is evidence for persistence of epigenetic effects being inherited over many (dozens? hundreds?, Im not sure) generations. I dont follow that field much, and cant vouch for it, but I have a lot of respect for Noble. Of course, he isnt exactly neutral, since he is a very strong anti-gene-centrism advocate.
Thanks, Dr Garte
I am following with another two questions . How would a trans-generational adaptive epi-genetic effect be detected? And if only some organisms exhibit it and others definitely do not, what do we make of it?
Left to my own devices I would say that all offspring (not just surviving offspring) must exhibit the change. In bacteria the descendants may be too numerous to see this, in more complex organisms, time may be a factor; we want results in our lifetime.
If only some organisms exhibit it, then it is not the counter idea/evidence to random mutations that I have seen bandied about on the Institute for Science and Culture Facebook page
I didn’t follow it at all, but I may have to read up on it a bit now. For some reason, reading through this part of the conversation, a question leaped to mind: What about instinct? Could epigenetics explain instinctive behaviors, which possibly began as an “ancestral memory”? A quick Google search turned up this gem:
(Here is a PDF of the article for those without full access.)
Following a few more rabbit trails led to something called the “Original Sin Hypothesis.” It attempts to explain the development of disruptive behaviors (aggression, opposition-defiance, rule breaking, and stealing-vandalism) in children.
Lots of food for thought …