An extreme allele of hooded spotting in the Norway rat.

A new allele (he) of hooded white spotting is described. The typical homozygous phenotype is an almost or completely white rat. The almost white animals have variable coloured spots on the sides of the head, usually around or above the eyes or covering the ears. Superficially, the eyes are dark but careful examination shows that pupil glows a dull red in bright illumination in all or the majority of individuals.