All wideband colors are practically the same gene makeup, but the rufus ‘r’ gene modifies how dark or light the coat is. White belly and eye rings are accepted because of the underlying agouti, ‘A’, gene. The frosty is the one one wideband that differs. A combination of wideband, ‘ee’ and the chinchilla ‘c(chd)’, the wideband gene blocks all the dark pigment found on a typical agouti while the Chinchilla gene blocks all orange pigment. What is left is a mostly white bunny with some dark tips scattered across the coat.