Several types of retinal defect intermediate between "rodless retina" of the mouse and normal retina were studied. Similar intermediates had been found in Basel stock. Such intermediates were not produced when C3H strain mice homozygous for "retinal degeneration" were outcrossed although the intermediate types and retinal degeneration type are allelic. However, such intermediates derived from a C3H outcross are described in the present paper. The intermediate condition here reported is recessive to normal retina, and acts as a dominant allel to the ontogenetically earlier developing retinal degeneration of the zero-row or one-row type.
Keeler CE. Reoccurrence of Four-Row Rodless Mice. Arch Ophthalmol. 1970;84(4):499-504. doi:10.1001/archopht.1970.00990040501020