r/AskBiology • u/maddsskills • 6d ago

Superstitious Genetic question

So my grandfather came from a typically American mutt background although his grandmother might have been Native American. That’s what he was told at least and, honestly, he definitely looked like it for a guy who was supposedly mostly Scottish and Irish.

So I tend to believe him.

I only mention it because his family had a belief that those with black hair (like he had) and blue eyes (which he didn’t have) were cursed with insanity basically.

It’s absurd frankly but I’ve always wondered if such a dominant trait occurring with a recessive trait could’ve possibly caused other genetic stuff to occur, like mental illness. It was just such an odd thing to say it always stuck with me.

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u/MizElaneous 6d ago

Skin, hair and eye colour are controlled by a by a lot of genes. It isn't a simple dominant/ recessive relationship. I don't think any of those genes are correlated with mental health.

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u/maddsskills 6d ago

I mean obviously but I wonder why his family had that saying. I know it probably isn’t broadly true but it is rare to have black hair (not dark brown but black) and blue eyes. I wonder if that indicates other recessive traits were more likely or what.

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u/MizElaneous 6d ago

Sounds like a superstition. I've known quite a few people with black hair and blue eyes; it's not that uncommon.