Occasionally when breeding, a newborn cat will possess a trait not seen in either of its parents. No – it’s not a sign of infidelity. When this happens, it’s known as a mutation. Unfortunately, your cat does not have superpowers (we wish). But it might have a cool new gene it can pass on to its offspring.
Each trait (or gene) in CryptoKitties is paired up with a partner gene. They’re largely unrelated, except that when these two genes are bred together there’s a chance that they’ll result in one of these new mutation traits not present in either parent.
Let’s run through an example of a mutation. The chart below shows that the savannah and selkirk furs are a partner pair. One look at the pair you learn they mutate into norwegianforest (gene 16).
The minimum chance to mutate if your two cats have the two required visible Cattributes can be up to 25% for Base Level genes (found in Gen 0), Tier 1 (M1) and Tier 2 (M2). The chance to mutate into higher tiers is 12.5% maximum. More on this below!
Kitties have four genes for each cattribute; a single primary, or dominant, gene, the one that gets expressed in the cat’s appearance, and three hidden, or recessive, genes, that do not. When two cats breed, they’re most likely to pass on their dominant genes. But there’s a smaller chance that one of their hidden genes will be inherited instead.
If the parents happen to pass on partner genes – hold on to your butts – there’s a chance for mutation.
Take these two for example. Both these cats are purebred, which means they have the same gene in all four slots of that Cattribute. One is a purebred with raisedbrow eyes and the other a purebred with fabulous eyes. They’re about to breed. Don’t make things weird.
Both parents have the same gene in all four slots, so the sire is guaranteed to pass on the raisedbrow gene, and the dame is guaranteed to pass on the fabulous eye gene. Fortunately for this example scenario, fabulous and raisedbrow are partner genes.
When combined these two genes have a 25% chance of mutating into the wingtips gene. There’s also a 37.5% chance of getting raisedbrow and a 37.5% chance of getting fabulous. But since this is a mutation example, you can probably guess what happens next.
This is what makes purebred cats particularly valuable for breeding. Because they’re guaranteed to pass on a certain trait, the odds of achieving a mutation are far greater than in cats with varied genes.
Would you look at that! Wingtips!
But what if you’re not lucky enough to have two purebred cats with the desired traits for breeding? Let’s say you have two Kitties with genes like this:
You’ve still got two cats with the raisedbrow and fabulous traits, so that’s good. Even better, those traits are both primary, so they’re the most likely to be passed on. There’s a 75% chance that the sire will pass on raisedbrow and the dame will pass on fabulous. If that happens, there’s a 25% chance that those two genes will mutate into wingtips. Taking into account all eight genes that could be passed, there’s a 14% chance that any one breeding instance would result in a cat with wingtips. Here’s the math:
0.75 * 0.75 * 0.25 = 0.14 = 14% chance of wingtips
This is all well and good, but what if your cats don’t have the desired traits as primary genes, but only as hidden recessive ones? For instance, a simple-eyed cat that just knows it has a fabulous-eyed cat somewhere deep inside?
Well, all is not lost. The sire has raisedbrow as a primary gene, a solid start. But the odds that the dame with simple eyes will pass on the fabulous gene is pretty low: only 1.5%. So the overall odds of getting a child with Wingtips from this pair breaks down like this:
0.75 * 0.015 * 0.25 = .0028 = 0.28%
Never tell me the odds, but...good luck with this one.
Breeding for mutations is when genetic calculators like KittyCalc become particularly helpful. They can break down the likelihood of every trait getting passed on, as well as the probability of a mutation occurring.
Base level gene - Some genes are released at gen 0, and these are called base level genes (INT 00-15). Certain pairs of these genes, when bred together, have a chance to mutate - two base level genes can create a first order mutation (M1, INT 16-23), two M1 genes can create a second order mutation (M2, INT 24-27), etc. The highest possible mutation is a fourth order mutation (M4, INT31).
The chance to mutate into first and second order genes can be up to 25%, but the mutation chance for higher order genes is only up to 12.5%.
What’s the point of getting a sweet mutation if nobody knows about it? That’s where Family Jewels come in. Jewels are awarded to the first Kitties that display a new mutation.