Below are a few genetic sites I use to help me remember the genetic traits of the various gene modifiers.

Sites for genetics:

Frank Mosca  - http://www.angelfire.com/ga3/pigeongenetics/index.html

Ron Huntley - http://www.angelfire.com/ga/huntleyloft/Page1.html

Tom Barnhart - http://www.barnhartlofts.com/genetics.htm