Tracking down the conservative/liberal gene

Can genes make us liberal or conservative?

If Jason Soon doesn't tweet this story, I'll eat my metaphorical hat.

The one thing I don't quite understand about the apparent genetic component to political beliefs, however, is how it explains the not uncommon phenomena of former quite extreme Lefties who convert to being extreme Righties.  (It sort of happens in the reverse direction too, I suppose, but not as often.)  The ranks of Catallaxy threads are full of people who claim they made the conversion, for example.   Is there just a genetic element to "it doesn't matter what I believe, I just must believe it 100% percent"?

Update:  my "hat" is safe.  I spent a while yesterday wondering whether I had correctly referred to it as "metaphorical" or not, and found it hard to work out a definitive answer from Google.