These sites can give you alot better definitions and explanation of bp genetics than I can:

http://www.newenglandreptile.com/genetics_intro.html
http://www.newenglandreptile.com/gen...recessive.html
http://www.newenglandreptile.com/gen...recessive.html
http://www.newenglandreptile.com/genetics_codom.html
http://www.ballpython.ca/genetics.html