
Phenotypic distribution of spontaneous mutant strains in the study. The cohort of mutant strains selected for exome sequencing represents various phenotypes that have an observable common characteristic during the course of normal breeding and husbandry. System level or tissue level mammalian phenotype (MP) terms were assigned on the basis of primary phenotypes. Phenotypes are arranged clockwise from largest to smallest group and similarly from top to bottom in the key.











