Flagg said:You don't want to breed 2 brindles together, yet another semi lethal gene. Plus most of them also contain the lethal yellow gene, which shouldn't be bred together from both parents.
"Brindle (Mobr). Brindle males usually dies between 10 and 14 days of age. Extremely few lives long enough to sire a litter. Brindle males suffer from a neurological impairment, as do homozygous females. This is characterized by a slight tremor and uncoordinated gait." from Eva's mouse genetics page