A strain of organisms bearing nonallelic recessive lethal genes, each in a different homologous chromosome. When interbred such organisms appear to breed true, because one-half of the progeny are homozygous for one or the other lethal gene and die prior to their detection. The surviving progeny, like their parents, are heterozygous for the lethal genes. See Chronology,1918, Muller; 1930, Cleland and Blakeslee.
Subjects: Genetics and Genomics.