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Can you explain what you're saying here? > I also take heritability to be quite controversial, since what is the point of the covariance of genes with traits a

Can you explain what you're saying here? > I also take heritability to be quite controversial, since what is the point of the covariance of genes with traits across populations? In almost all cases this isn't informative of anything

mjburgess 2y ago
If there's no simple linear gene-trait relationship, then how inheritable a trait is will not be tracked by heritability which is a statistic of covariance across a population. This problem becomes compounded in the extreme if there's any environmental modulation of the trait-gene relationship. Consider that a scottish accent is nearly 100% heritable: it entirely covaries with genes (localized in scotland), but is 0% inheritable. Suppose eye colour is 100% inheritable, but a product of 100 gene interactions, which have substantial geographical localization. You could easily find a case where heritability of eye colour was 0%, but inheritability 100%. Heritability is a dumb metric for charlatans anyway, even in a simplified trait-gene world -- but in the actual world we live in, >99% of its uses constitute pseudoscience. It was originally invented for working in agriculture where population were under genetic control by experimenters -- here the covarience is actaully causally indued by experiment, forcing a much simpler and deterministic relationsihp between genes and traits. In basically all other cases it's meaningless.
- Myrmornis 2y ago
  Right, thanks. But, at least for the last half century, statistical analyses in quantitative genetics have included genetic and environmental effects in their models, i.e. explicitly trying to find evidence for genetic influences after taking into account environmental effects. (I'm not saying it's easy to do so).
  - mjburgess 2y ago
    Yes, and those models are still based on a simple trait-gene relationship. They're linear additive models. The whole thing is pseudoscience.

mjburgess 2y ago

If there's no simple linear gene-trait relationship, then how inheritable a trait is will not be tracked by heritability which is a statistic of covariance across a population. This problem becomes compounded in the extreme if there's any environmental modulation of the trait-gene relationship. Consider that a scottish accent is nearly 100% heritable: it entirely covaries with genes (localized in scotland), but is 0% inheritable. Suppose eye colour is 100% inheritable, but a product of 100 gene interactions, which have substantial geographical localization. You could easily find a case where heritability of eye colour was 0%, but inheritability 100%. Heritability is a dumb metric for charlatans anyway, even in a simplified trait-gene world -- but in the actual world we live in, >99% of its uses constitute pseudoscience. It was originally invented for working in agriculture where population were under genetic control by experimenters -- here the covarience is actaully causally indued by experiment, forcing a much simpler and deterministic relationsihp between genes and traits. In basically all other cases it's meaningless.

Myrmornis 2y ago
Right, thanks. But, at least for the last half century, statistical analyses in quantitative genetics have included genetic and environmental effects in their models, i.e. explicitly trying to find evidence for genetic influences after taking into account environmental effects. (I'm not saying it's easy to do so).
- mjburgess 2y ago
  Yes, and those models are still based on a simple trait-gene relationship. They're linear additive models. The whole thing is pseudoscience.