Persistence of a lethal t haplotype in a laboratory stock of outbred mice

Abstract

SUMMARY: A cryptic, lethal t haplotype (named t^Lmb) has been discovered in the non-inbred MF1 laboratory stock of mice. Detailed genetic and molecular studies demonstrate a close relationship between t^Lmb and a well-studied t haplotype, t⁶, previously extracted also from a laboratory stock. It appears likely that t⁶ is an aberrant t haplotype derived by recombination from a t^Lmb-like ancestral chromosome. The persistence of t^Lmb through 40 years of random breeding in a laboratory stock indicates that high transmission ratio distortion is sufficient to overcome the deleterious effect of a recessive lethal gene in a mouse population.