Fitness of heterozygotes of deleterious recessive mutations in the mouse

Abstract

The hair-deficiency mutation ƒs (furless) and the neurological mutation shm (shambling) are both recessive deleterious mutations of the mouse. They both depress the viability of homozygotes. Shambling mice weigh less and have shorter lives than their non-shambling littermates. Experimental attempts to detect effects of these mutations on the reproductive fitness of heterozygotes, ƒ s/+ and shm/+, gave negative results. Also ƒ s/+ mice were not more radiation-sensitive than +/+ mice.