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.
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.
This is a nice discussion of these issues. In defense of the head of search and rescue team, if a bunch of concerned citizens (SNP-genomics) are claiming that the hiker isn't really lost but instead went over to a friend's house to smoke pot and play video games, then it is valuable to confirm that the hiker really is out in the woods, lost, and needs help.
Any phenotype has its quirks, but you chose alcoholism, so let’s start there. Assuming the adopted child in question was (almost impossibly) not exposed to significant amounts of alcohol as a fetus, and you already know that there aren’t any significant genetic variants related to alcoholism (I assume your “exception” is aldehyde dehydrogenase variants), what exactly is your concern? One of our society’s dirty little secrets is the level of alcohol consumption one might see if they peruse the garbage of their neighbors. It is pervasive in our culture and dominates most social gatherings. Moreover, some families are completely tied to alcohol consumption and some cultures (I won’t bother getting specific) revolve around alcohol consumption. So there are easy enough ways to see how someone from a particular family or genetic ancestry are going to be more likely alcoholic by whatever definition, without any regard for genetics. So when you correlate genes to alcoholism and you find some pittance of variance explained, consider the possibility that even that is inflated, rather than searching for missing heritability. You are again left only with twin studies. You have effectively nothing else. And it is tiresome to watch people take what is “effectively” nothing to mean “so you’re saying there’s a chance”? It doesn’t score any points to refer to others as “absolutist”, while you are holding 7 high in your poker hand, when we all know there was a lot of bluffing about three Aces that preceded that. The truth of the matter is that behavioral genetics lacks a certain integrity, if there is a constant pursuit of missing heritability, while no one is writing papers considering whether the whole thing is a wash (effectively or absolutely).
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.
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.
This is a nice discussion of these issues. In defense of the head of search and rescue team, if a bunch of concerned citizens (SNP-genomics) are claiming that the hiker isn't really lost but instead went over to a friend's house to smoke pot and play video games, then it is valuable to confirm that the hiker really is out in the woods, lost, and needs help.
The search and rescue team only gets paid for a rescue, and mysteriously doesn’t check the friend’s house to see if he is there.
Any phenotype has its quirks, but you chose alcoholism, so let’s start there. Assuming the adopted child in question was (almost impossibly) not exposed to significant amounts of alcohol as a fetus, and you already know that there aren’t any significant genetic variants related to alcoholism (I assume your “exception” is aldehyde dehydrogenase variants), what exactly is your concern? One of our society’s dirty little secrets is the level of alcohol consumption one might see if they peruse the garbage of their neighbors. It is pervasive in our culture and dominates most social gatherings. Moreover, some families are completely tied to alcohol consumption and some cultures (I won’t bother getting specific) revolve around alcohol consumption. So there are easy enough ways to see how someone from a particular family or genetic ancestry are going to be more likely alcoholic by whatever definition, without any regard for genetics. So when you correlate genes to alcoholism and you find some pittance of variance explained, consider the possibility that even that is inflated, rather than searching for missing heritability. You are again left only with twin studies. You have effectively nothing else. And it is tiresome to watch people take what is “effectively” nothing to mean “so you’re saying there’s a chance”? It doesn’t score any points to refer to others as “absolutist”, while you are holding 7 high in your poker hand, when we all know there was a lot of bluffing about three Aces that preceded that. The truth of the matter is that behavioral genetics lacks a certain integrity, if there is a constant pursuit of missing heritability, while no one is writing papers considering whether the whole thing is a wash (effectively or absolutely).