Artificial selection will work if a trait has any positive heritability, that is, if any proportion of the total variation in a trait among individuals in a population is due to genetic variation — what we specifically call "additive genetic variance" in the trade. And virtually all morphological or behavioral traits have some positive heritability.Actually, eugenics wouldn't work in humans because reason and personal choice can frustrate efforts at programming.
Look at domestic dog breeds, for instance. All of them descend from the wolf, yet all the huge variety of their traits: the variation in their size, their shape, their color, and even their behavior (retrievers, border collies, etc.) have come from selecting on traits that have a positive heritability. As Darwin said in The Origin, "Breeders habitually speak of an animal's organization as something quite plastic, which they can model almost as they please."
That happens to be true. And it would be true of humans as well if we were able to select on them.
Jerry Coyne, "Dawkins makes a tweet" at Why Evolution Is True
Comment: Not to mention the fact that great people can be born to monsters, and vice versa.
Another issue was raised by a reader who reminds us that, in any event, dog breeding is devolution for dogs. It usually works that way, as Michael Behe points out in Darwin Devolves. Dogs are bred by humans at the expense of their genetic health. Some call it "malgenics."
That's quite correct. Domestic dog breeds often have serious inbred problems that the feral cur never knew. He stays alive despite all those who want to kill him. The pampered pedigreed with the fashionable but costly features might expire despite the vet's best efforts to save him. - News
Comment: It's things like this that show why you shouldn't automatically trust experts. They're often experts at being idiots. But their 'expertise' goes to their heads, inflating their self-importance, and the conviction that they actually know what they're doing. It's people like Dawkins and Coyne who rationally explain why things "should" or "will" work, when the actual implementation of their plans and policies results in disaster because they were either completely wrong to begin with, or were unaware of hidden variables. Don't trust experts to come up with solutions that don't already have a good track record.
Geneticist Dave Curtis has a useful Twitter thread on why eugenics just wouldn't work on humans.
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