Development of Dickie's small eye: an early lethal mutation in the house mouse.

Mice heterozygous for Dickie's small eye (Dey) are small and have malformed eyes (Theiler et al. 1978). The development of homozygous Dey/Dey was more difficult to analyze than heterozygous Dey/+. This investigation to identify the homozygotes and to distinguish them from Dey/+ and +/+ resorptions. Such a distinction was possible only when enough specimens were available. The mutants are poor breeders and the collection of the necessary material has taken several years.