Hereditary Degeneration of the Mouse Retina

TRUE hereditary degeneration of the retina has been described in the rat (Bourne, Campbell, and Tansley, 1938) and the dog (Hodgman and others, 1949), but certainly not in any other species. . In a series of papers, Keeler (1924, 1926, 1927, 1928) described an inherited retinal anomaly in the house mouse which he called " rodless retina ". This anomaly is inherited as a Mendelian recessive character and the mice are blind by conditioned reflex tests. In addition, no electro- retinogram could be obtained from them (Keeler and others, 1928). Keeler claims that the condition is one of arrested development, the retina developing normally until 6 or 7 days after birth but not thereafter progressing beyond the separation of the inner and outer fibre layers. No rods ever develop, and there is said to be a reduction of normal mitotic activity from birth onwards (foetal eyes were not examined) and no degeneration. Such a condition could obviously not be considered as a retinal degeneration.