"Can there really be a liberal gene? They’ve got to be joking. But no here it is, straight from Fox News today: James Fowler, a professor medical genetics and political science says liberals can’t help being – liberal. Of course, what Fowler calls the “liberal gene” he also explains as being the “open minded” gene. " (The Liberal Gene)
This may seem pretty out there but it's believable. Traits, including personality, are inherited from your parents, so why not the ability to be open minded. However, I don't think you can call this gene the "liberal gene" because your political views, while they may be influenced by your parents, are not directly inherited from them.