Friday, October 12, 2012

Things They Should Study: does sibling resemblance run in the family?

I recently saw a picture of a large family where all the children are blond, and my first thought was that it was kind of creepy but I couldn't articulate why.  After some thought, I realized it's because I'm not accustomed to seeing a whole family of blonds.  All the blonds in my own family, as well as nearly every blond kid whose siblings I knew growing up (I can only think of one exception), have at least one brunette sibling.

Siblings tend not to resemble each other especially closely in my own family.  My sister and I don't share colouring, shape, bone structure, or any distinguishing features.  Among my relatives, siblings who share colouring don't share bone structure, and siblings who share features have them in different colours. If you put us all together collectively you can see that some people might be related to others, but you'd never be able to tell who is siblings with whom.

And yet, siblings with strong resemblances do exist.  And sometimes, like with the family of eerily similar blonds, all the siblings in a given family resemble each other.

It would be interesting to see if there's some kind of genetic reason why some families have strong sibling resemblance and others don't.

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