Well, I'm just speculating here, but since they have many colors, including white, buff, etc., I would also suggest that they have inherited a gene for docile behavior.
'Nova' or 'Nature' did an episode about domesticating the dog a few years ago, and I caught a rerun of it a couple weeks back. Russian geneticists in the 1950's through the 1970's worked extensively with foxes, trying to develop more docile foxes that would do better in captivity for fur farming (poor things, but that's a whole 'nother issue).
Anyway, they bred for the foxes that were the least agressive and most docile. After a few generations, not only did their behavior change, but suddenly the pups were born with all kinds of colors and patterns, including a lot of white.
http://docs.google.com/viewer?a=v&q...b9et6N&sig=AHIEtbRSTdWM2I6EpEwWmyvGdWKwqUp0bQ
I honestly think my Coturnix are at least as friendly as my chickens. They really are fun, and it's cute to watch them come running up to see what I'm bringing them. A far cry from any other quail I've ever known or heard of, for the most part.
Curiously, my button quail have all of the exact same color patterns, basically, but they are still very wild and timid acting.
