Inheritance of Congenital Palsy in Guinea-Pigs

Abstract

1. A definite neurosis appeared in our guinea-pig stock in 1914, characterized by clonic spasms, particularly of the legs. When in a spasm the animals lie on their sides in a helpless condition. This state is induced by various stimuli, but especially by those of a sharp auditory nature, and also by attempted volitional movements of the legs. 2. The affected animals, are fully up to average weight when born, and appear to be normal in all other respects. While different individuals vary with respect to the intensity of the symptoms at birth, they are always easily distinguished from normal young, and in all cases the disease runs a short progressive course, terminating in death within about two weeks at most. 3. This defect, which we have called congenital palsy, is definitely heritable. It is a simple Mendelian recessive, and normal and affected offspring are produced by two heterozygous parents in the ratio of three normal to one affected. 4. It has been shown that heterozygous animals mated to normals produce offspring of the same classes as themselves in equal numbers. Furthermore; it has been proven that homozygous dominants can be extracted from heterozygous parents and that they show no more tendency to transmit the disease than individuals of normal unrelated stock. 5. Heterozygous animals are entirely normal in their reaction and can be told from the homozygous only by breeding tests. 6. A survey of the literature relating to nervous defects in man and other animals does not reveal any condition corresponding exactly to congenital palsy. Some of the conditions in pigeons, rodents and in man are similar in that they are recessive in inheritance.