Breeding Outcomes

Dominant and Recessive Genes

Unlike traditional genetics, where dominant and recessive genes have to do with the traits themselves (e.g. blond hair is recessive to black hair), CryptoKitty genes are dominant and recessive based on where they are located in the kitty’s genome, and it affects what gets passed to offspring.

kai genome truncated
(Dominant gene is D0 and recessive genes are R1, R2, R3.)

How do traits get passed on to offspring?

There’s an article about how recessive genes are be passed onto children here, but here’s the gist of it. The probabilities that the kitten will inherit one of its parent’s traits are:

odds 1

Here’s an example. Let’s say I breed together my two cats, Strawberry and Cookie, and I want to find out what body pattern their kitten might have. I look at their genes first.

odds 2

Here are the possibilities for the offspring’s pattern traits and each one’s likelihood.

Calicool: 37.5% + 37.5% + 0.8% = 75.8%
Luckystripe: 9.4% + 9.4% = 18.8%
Totesbasic: 2.3% + 0.8% = 3.1%
Spock: 2.3%

You’ll notice that the bolded numbers sum to 100%.

Genetic Mutations

There is an exception. When certain pairs of traits encounter each together, they have a 14% – 25% chance of mutation. Please see my blog post on mutations for more information.

Offspring Trait Calculator

If you don’t want to do all this math yourself, use a breeding calculator like KittyCalc or KittyAppX. Just input the kitty # for each parent and it will tell you the odds of getting certain traits in your offspring. (The calculators are more accurate than my example above because they take mutations into consideration.) If you want to know the odds of getting two traits simultaneously (e.g. cymric AND tongue), just multiply their probabilities together.

Visualizing the Odds

Breeding outcomes looks somewhat similar to a normal curve. Imagine that the sire is the left side of the curve and the dame is the right side. The D0 genes are the green sections, R1 genes are yellow, R2 is red, and R3 is blue.

ck almost normal curve
CryptoKitty Almost-Normal Curve

For help interpreting your kitty’s genes, see How to Read Your Kitty’s Genes and the Gene Reader Spreadsheet.

Happy breeding!

A special thank-you to and AppX Matthew for the breeding calculators!


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