zlacker

>>qqqqqu+(OP)
Another frustrating one - what is heredity? If it's possible to inherit something due to a shift in behavior (i.e. it's a cultural change that leads to a biochemical change), how does that connect neatly to mendalian inheritance?

>>qqqqqu+d6
Are you talking epigenetics? It's relatively closely related to mendelian inheritance. At a high level view, if genes are present in your genome that aren't "on" in a previous generation, but due to changes in behavior become more active, then in a future generation that gene could be expressed more. It's not that the genes have changed their code, they are just flipped on or off.

>>epmayb+R8
No, more things that are modifications without any genetic basis - like myopia. Doesn't seem to have any genetic/epigenetic basis. It's purely a physical use case, where the eye matures improperly if it's only exposed to near-field work.

>>qqqqqu+h9
ah, I see what you're saying. Luckily, I've looked into this specific topic!

Myopia is definitely hereditary, especially the pathologic variants that can lead to retinal tears and the like.

That being said, there is the process of refractive development that occurs early on in life. The eye develops at a frighteningly fast pace, and you achieve near-adult globe size after about 18 months. The genes that drive this refractive development could be hereditary, if that is what you're trying to figure out.

Now, we can make a claim that this adaptation during infancy could eventually affect our genome, but I have not delved into the epigenetic literature to determine if that has been borne out or not.

>>epmayb+9n
90% saturation in a few generations suggests that it is something other than purely hereditary mutations accumulating: https://www.nature.com/news/the-myopia-boom-1.17120

>>qqqqqu+ZZ
I know, I'm not saying that these are hereditary mutations. I'm saying that genes in all of us are involved in refractive development, and thus have to be inherited if mutations exist. I'm saying that our environment of myopic environments is feedback that forces our eyes to develop to support better focus at those distances.