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The central problem is that people don't understand what "heritable" or "genetic" really means. Every trait you can possibly think of has a genetic basis. I.e
by araneae 17y ago
The central problem is that people don't understand what "heritable" or "genetic" really means. Every trait you can possibly think of has a genetic basis. I.e. having green hair is heritable, because people who dye their hair funny colors are more likely to be risk takers, and those personality traits are more likely in people with a higher fraction with such-and-such neurotransmitter receptors, and the number of those receptors is influenced by some gene by a few percentage points.
Just because it's genetic doesn't mean it's meaningful, anymore than it's really meaningful to say that this mutation which means you have 1% more of x receptor makes you go out and dye your hair green. It's ridiculous, and that's the kind of relationship that all these genes have with pretty much all phenotypes. The reason the effects are so small is because what the gene does is so far removed and from whatever phenotype you're studying. (usually)
- goodside 17y ago'The central problem is that people don't understand what "heritable" or "genetic" really means.' Apparently so. Heritability does not mean genetic causation. Language is extremely heritable (that is, children almost always speak the same language as their parents), and not because there's a long just-so chain of genetic and hormone events that ends in an innate facility for Cantonese.
- cabalamat 17y agoThat's true, but having said that, there are alleles that affect the nature of the language people speak. So there are alleles that give onre better facility at speaking tonal languages, and those alleles are (surprise, surprise) more common among populations that speak tonal languages (such as Chinese).
- tokenadult 17y agoSo there are alleles that give one better facility at speaking tonal languages Could you kindly provide references to a scientific study making that claim? I ask as a speaker of Chinese who learned Chinese as a second language.
- gort 17y ago"Heritability" means something like "how much of the variation in a population is due to genetic differences". This leads to some odd results, e.g. number of arms has low heritability (almost all variation is due to environment). Anyway, language is not heritable. The variation in the languages people speak in a population is not due to genes but rather to environmental effects.
- goodside 17y agoThis is right. Readers, please mod down my comment above for being simultaneously snarky and dead wrong.
- carbocation 17y ago"The reason the effects are so small is because what the gene does is so far removed and from whatever phenotype you're studying." ... unless you study a medically relevant phenotype, in which case the genes are often just a few steps away (namely, transcription and translation, with processing thrown in for good measure). I would agree that heritability is not all that meaningful (though technically valid) when talking about behavioral traits, though.
- araneae 17y agoThere's no reason that medically relevant phenotypes would be that much less complicated (and lets remember that mental health, is, in fact, medically relevant.) Yes, there are a select few, rare, single nucleotide polymorphisms that are responsible for congenital genetic defects. But plenty of disease involves the interactions of thousands of genes, like cancer, and for those it's really just as meaningless.