Abnormal urogenital organs occurring spontaneously in inbred ACI and Kyoto-notched rats.

Spontaneous malformations of urogenital organs found in inbred rat foetuses of ACI/NHok strains were further investigated with a postnatal survey involving other inbred strains. A new type of malformation occurred in Kyoto-notched rats. The present findings suggested that the malformations have different hereditary characteristics caused by different maldevelopmental mechanisms and are probably due to recessive polygenes.