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AFAIK, the consequences of DNA depend as much or more on the processing of them by RNA and otherwise than on the original genes. I wonder how the theory account

AFAIK, the consequences of DNA depend as much or more on the processing of them by RNA and otherwise than on the original genes. I wonder how the theory accounts for that (I'm not pointing out flaw as an armchair cynic, but asking a question.) Also, obviously environment plays a major role in our lives and I'm certain Plomin would agree: Abusive parents (or no parents), childhood experiences (think of rape survivors), education, the opportunities around us, access to resources, etc. etc. I would guess he's talking about an essential psychological nature that may determine how we respond to those things. My question is, where does he draw the line between that 'essential nature' (accepting for sake of argument that it exists) and environmental influence? EDIT: "Plomin’s argument is that, in a society with universal education, the greatest part of the variation in learning abilities is accounted for by genetics, not home environment or quality of school– these factors, he says, do have an effect but it’s much smaller than is popularly believed." Calling it "universal education" (the Guardian's paraphrase, not necessarily Plomin's words) is a big stretch - it's so different in different places, including in the same country, that it doesn't all fit under one term. Without more specific claims, it's hard to address that quote but I was reading in the last year about one poor school district which had accomplished a milestone: Half the third graders could read. Half those kids are in deep trouble, and I don't think that's due to genetics.

iguy 8y ago
Re processing of DNA etc, this isn't the level these studies are typically working at. There's no biochemistry knowledge involved. They are just looking at DNA sequences, and what data they have about outcomes. Whether a piece of DNA makes something critical for some muscle, or is 10 steps away in part of some complicated switching apparatus, of indeed just influences something else which causes the growing animal to enjoy behaviour which happen to exercise this muscle -- all of this detail is a black box, all of these would contribute to genetic effect. Re universal education, etc: in adoption studies this translates to "among parents who will be approved to adopt", and this indeed cuts the very bottom off the distribution of some factors. I don't think it's a huge issue, but not an expert. But my understanding of the point Plomin is making there is a bit different. Regardless of the current state of (say) schooling, he's pointing out that moving from a system with large schooling inequalities, to a system of absolute schooling equality, would almost certainly increase the heritability of education. In the unequal system, some bright kids are stunted etc, weakening the correlation between input and output; but in the equal one, all the variation in the output will be driven by the input. At least I think that's what he's saying. Haven't read the book, and not really my field at all...
- forapurpose 8y ago
  Thanks. Good point about the DNA 'black box'.

iguy 8y ago

Re processing of DNA etc, this isn't the level these studies are typically working at. There's no biochemistry knowledge involved. They are just looking at DNA sequences, and what data they have about outcomes. Whether a piece of DNA makes something critical for some muscle, or is 10 steps away in part of some complicated switching apparatus, of indeed just influences something else which causes the growing animal to enjoy behaviour which happen to exercise this muscle -- all of this detail is a black box, all of these would contribute to genetic effect. Re universal education, etc: in adoption studies this translates to "among parents who will be approved to adopt", and this indeed cuts the very bottom off the distribution of some factors. I don't think it's a huge issue, but not an expert. But my understanding of the point Plomin is making there is a bit different. Regardless of the current state of (say) schooling, he's pointing out that moving from a system with large schooling inequalities, to a system of absolute schooling equality, would almost certainly increase the heritability of education. In the unequal system, some bright kids are stunted etc, weakening the correlation between input and output; but in the equal one, all the variation in the output will be driven by the input. At least I think that's what he's saying. Haven't read the book, and not really my field at all...

forapurpose 8y ago
Thanks. Good point about the DNA 'black box'.