3 ms·
It seems the key problem that incites controversy is that when geneticists say "heritability," it doesn't mean what lay-persons think it means, and sometimes, e
by qiqing 8y ago
It seems the key problem that incites controversy is that when geneticists say "heritability," it doesn't mean what lay-persons think it means, and sometimes, even professionals in the field get caught up in defending the wrong arguments.
To the HN crowd, here's a simple but precise definition. Heritability is the extent to which variability (e.g., the standard deviation) of a trait in one generation can be explained by the variability of that trait in the previous generation. Note that high heritability does not mean that the trait is genetically based.
Fun fact 1: since most people are raised by their parents, religion and political party affiliation are also highly heritable, but no one is suggesting that there's a genetic basis for religion or political views.
Fun fact 2: number of fingers per hand is not very heritable. Since most people who have a non-five number of fingers per hand acquired that trait non-genetically (e.g., via an accident), the variability of this trait in the population correlates very little with the variability of the trait in the previous generation.
- ericdykstra 8y ago> Fun fact 1: since most people are raised by their parents, religion and political party affiliation are also highly heritable, but no one is suggesting that there's a genetic basis for religion or political views. Religious and political views being influenced by genetics is not only a completely valid hypothesis, but the most likely. Cultural environment is downstream of genetics, and although cultural memes look like they evolve, they're trickster replicators: subservient to genes.
- nordsieck 8y ago> To the HN crowd, here's a simple but precise definition. Heritability is the extent to which variability (e.g., the standard deviation) of a trait in one generation can be explained by the variability of that trait in the previous generation. Note that high heritability does not mean that the trait is genetically based. > Fun fact 1: since most people are raised by their parents, religion and political party affiliation are also highly heritable, but no one is suggesting that there's a genetic basis for religion or political views. You're wrong. There are separated twin studies; they rule out stuff like "parents, religion and political party affiliation". There may in fact be some other mechanism by which heritability works, but it would have to be physical, and it would have to act in ways indistinguishable from genetics. Also, there are plenty of people suggesting that people's religion and political views have a genetic component.
- tomhoward 8y agoAn important question here are whether we're talking about immutable genetic encoding vs genetic expression (sometimes more controversially known as "epigenetics"), which is mutable via environmental stimuli, experiences, beliefs, traumas, cultural influences, etc. The follow-up question to that is the extent to which one's epigenetic state at birth is determined during gestation and influenced by the mother's beliefs and experiences (as well as the father's indirectly via the mother). This would explain why some correlations are found in twin study results, but also why those correlations are never close to 100%. It would also explain the study results that suggest inheritance of patterns like trauma/anxiety e.g., in descendants of holocaust survivors. I'm fully aware this area is nascent and yet to be deeply researched, but hypotheses exist that are plausible and potentially explanatory of phenomena that are otherwise still unexplained.
- dragonwriter 8y ago> but no one is suggesting that there's a genetic basis for religion or political views. Yes, they are. They generally aren't claiming that those things are as strictly genetically determined as eye color, but there have been arguments that tendency toward certain kinds of religious and political views had significant genetic contribution.