September 13, 2012

Genetics and The Weasley Family

You can't see everyone's hair in this photo,
but trust me, they're all redheads.
It's always frustrated me that the entire Weasley family are redheads.
Yes, I will give a pass to all the magical happenings in the Harry Potter stories, but it's annoying (and genetically unlikely) that two redheads will meet, and that all seven of their kids will have red hair!
This article on Boing Boing, debunking the myth that redheads are being bred out of existence, points out:
"Only 1% of humans are redheads, but 4% of humans carry a copy of the gene that makes redheads. You could be a carrier and not even know it. So could your spouse. Two redheads are unlikely to make a brunette, but two brunettes can make a redhead."
I am assuming that Muggle genetics and Magical genetics work the same way!
It's easy to assume there are more redheads in England than the worldwide average of 1%, so it's not extrordinary for Arthur and Molly Weasley (the parents) to find each other. But what are the odds of all seven offspring having red hair? Anyone know?