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Sasha Gusev's avatar

As far as I'm aware the most direct paper from Visscher that touches on this question is Robinson et al. 2017 (https://pubmed.ncbi.nlm.nih.gov/28692066/) which localizes a significant portion of heritability to gene-environment interactions and contains fairly unequivocal claims: "Taken together, population studies imply that estimates of h2 for BMI are systematically inflated in classical twin studies." (in the introduction) and "Therefore, we suggest that genotype–age and genotype–environment effects may contribute to the inflation of BMI heritability estimates in classical twin studies, in combination with stronger common environment effects in close relatives than more distant ones." (in the conclusion). I think the field has generally not grappled with the implication of substantial gene-environment interactions and what this means for how we think about and predict complex traits.

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DC Reade's avatar

I'd be interested in learning if there's a heritable overlap or synergy between alcoholism and diabetes (either type 1 or type 2.) "Alcoholism" may not be just one phenomenon, for that matter. Perhaps there's one variant with a link to impaired sugar metabolism, and another independent of that interaction.

Alcohol use as an example is particularly intriguing, because the "environmental" influence of social and cultural (including subcultural) factors is also widely held to be prominent. (I'd say that's indisputable.) Including legacy and historical factors: the acceptability of alcohol use in social environments and as a cultural practice is mutable over time, and there are examples to be found where a change in social attitudes has asserted itself quite swiftly and decisively.

Alcohol use is also a practice where dramatic examples can be found, ranging from social groups and cultures where alcohol is forbidden, to the opposite extreme of common resort to volume drinking of distilled liquor in a social milieu where the option of moderation is rarely if ever pursued, or even considered as an individual choice. There are also often notable culture-dependent differences in consumption habits between males and females.

So there's a lot of grist worth studying, both in terms of sampling population genetics and researching the relative importance of sociocultural factors.

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