Mouse genotype calculator
Pick the parents’ genotypes to see what share of pups each genotype will be, and how many pups you need.
25% of pups will be Gene 1 KO (-/-). For 10, expect about 40 pups, about 7 litters of 6.
| Gene 1 | Share of pups |
|---|---|
| HET (+/-) | 50% |
| WT (+/+) | 25% |
| KO (-/-) | 25% |
CageCard records every mouse’s genotypes and parents, and shows the expected ratio next to each litter’s results. Try it free for 30 days.
How it’s worked out
Each parent passes one of its two copies of each gene, with equal chance, and genes on different chromosomes are inherited independently. So each gene gives its own split (Het × Het: 25% WT, 50% Het, 25% KO; Tg/0 × 0/0: 50% each), and the share for a combination is the product of the genes’ shares. Choosing one sex halves it.
Pups needed = mice needed ÷ share, rounded up. Litters = pups ÷ average litter size, rounded up.
Example: Cre (Tg/0) × flox/flox, wanting flox/flox and Cre: 100% × 50% = 50%. With flox/+ × flox/+ instead, it’s 25% × 50% = 12.5%, so 10 mice take about 80 pups.
Averages only: litters vary, and pups lost before weaning aren’t counted. Genes close together on the same chromosome are linked and don’t follow these odds.
Sources
- The Jackson Laboratory: Breeding strategies for tissue-specific knockout mice
- The Jackson Laboratory: Cre-lox breeding scheme
Last checked against these sources on . Found a mistake? Tell us.