Oh also, read this. GREAT crash-course on genetics.

http://www.ballpython.ca/genetics_101.html

Honestly, the only reason I know anything about het versus homozygous and and all that jazz is because I have forgotten more than most people will ever even KNOW about horse colour genetics. Ironically once you get the hang of recessive, co-dom aka incomplete dominant and dominant inheritance, it doesn't matter what species it is. Show me a horse, and I can tell you with some degree of certainty what colour it's parents were. Show me a pair of horses and I can tell you what you are most likely to produce. It translates well into Ball Python morph genetics, ironically enough.