They have. Believe it or not, the gene that controls the direction hair grows in is the same in fruit flies, mice, and humans. (In the case of fruit flies, it's the hair on their legs, if you're wondering.) They've also found people whose hair is unusually unruly are prone to certain neurological problems, probably because one of the genes that control hair direction also lays out the pattern of nerves underneath it.

Human hair patterns are also linked to left and right handedness. Think of "mirror twins" - identical twins, except they are mirror images of each other. One has hair parted on the right, one has hair parted on the left. And one is right handed, the other left handed.