Phenotypic Expression of the Mutant Gene diabetes insipidus in Rats and Criteria of Genotyping by Phenotype

The autosomal semidominant mutant gene di(diabetes insipidus) is manifested in homozygotes in the form of diabetes insipidus with water consumption from 25 to 100% of body weight per day. The heterozygotesdi/+ drink water at a rate higher than 5% but lower than 25%. The level of water consumption in rats with +/+ genotype does not exceed 5% of body weight per day. Segregation analysis of F₁ animals yielded by various crosses showed that genotyping of di/di homozygotes is absolutely reliable at 30% and higher level of the water consumption per day.