Genotypes for individual mice and pairs
Genotypes for Individual Mice
Genotypes for individual mice are included with the strain detail for each mutant strain. Whenever possible, we provide homozygotes for recessively transmitted mutant alleles (including most targeted mutations). However, homozygotes for some mutations, cannot be provided because they die in utero or perinatally, are too fragile to ship, or are produced in extremely low numbers (either they are not in high demand or they reproduce poorly). In such cases, we provide only hemizygotes, heterozygotes, or the pairs of mice needed to produce the mutant. The individual mouse genotype for such strains is designated “heterozygote only; (affected mutant not avail.).”
In contrast, we usually provide heterozygotes for genes and alleles transmitted dominantly or semi-dominantly. Because transgenes are transmitted dominantly, transgenic mice are provided as hemizygous (transgenes incorporated on only one member of the homologous chromosome pair) or as homozygous (transgenes incorporated on both members of the chromosome pair). To expedite the distribution of some high-demand transgenic strains, we denote their genotype as “Tg/?.” Such mice carry the transgene but are not confirmed as either homozygous (Tg/Tg) or hemizygous (Tg/– or Tg/0). Strains with a genotype of “Tg/?” are also made available to investigators if genotyping protocols are being developed and test matings are being completed.
Genotypes for Breeder Pairs
The genotypes of breeder pairs used to produce many mutant strains are included with the mutant strain’s detail. Because of the breeding scheme used to produce a mutant, its genotype may differ from those of its progenitor pair. Genotypes for standard pairs are included with the strain detail. If a breeder pair with genotypes other than those listed is needed, please contact Customer Service.
Breeder pairs of strains heterozygous for some spontaneous mutations are identified by progeny testing rather than by DNA typing. Progeny testing involves observing affected pups produced by breeder pairs of an unverified genotype. Pairs proven to be heterozygous by progeny testing are distributed as “tested.” Otherwise, they are distributed as “untested” and designated as “+/? x +/?.” To assure that untested breeder pairs have the spontaneous mutation of interest, we recommend purchasing more than one pair.
