The Warrior Gene in MMA-fighters?

I've always been interested in the psychology of fighting and fighters and a while back I mentioned that maybe some UFC-fighters have the so called Warrior Gene(MAOA) that is found in psychopathic and serial killers.

Yesterday I found this little docu-program actually testing a few (south african?) cage fighters for the Warriro Gene and I thought it was interesting:

http://www.youtube.com/watch?v=g6UtV0d9DcE

Mods, if you deem it unrelated pls move.