Cat Color Genetics Calculator (Kitten Colors)

Kitten colour odds by sex from the parents' orange (sex-linked) and dilute genes: black, blue, red, cream, tortie.

Orange is carried on the X chromosome, so a male kitten's colour comes from his mother alone and a female needs orange from both parents to be orange. A tortoiseshell queen bred to a black tom gives half orange and half black sons, and half tortie and half black daughters.

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How to use it

  1. Choose the mother's and father's colour (orange gene).
  2. Choose whether each parent is dilute, carries dilute or is dense.
  3. Read the chance of each kitten colour by sex.

What you enter

What you get

Formula

Orange (O) is X-linked: males XᴼY or XᵒY; females XᴼXᴼ, XᴼXᵒ (tortie), XᵒXᵒ | Dilute (d) is autosomal recessive

Worked example

Input: Tortie queen carrying dilute × black tom carrying dilute

Result: Females: 37.5% tortie, 37.5% black, 12.5% blue-cream, 12.5% blue; males: 37.5% red, 37.5% black, 12.5% cream, 12.5% blue

Sons take after their mother's X; daughters can be tortie.

Questions

Why are almost all calico and tortoiseshell cats female?

Tortie needs one orange X and one non-orange X. Males have only one X, so a tortie male must be XXY (Klinefelter), which is rare and usually sterile.

Can two black cats have orange kittens?

No. A black female has no orange allele and a black male passes no orange to daughters, so neither sex can be orange.

Where does a grey (blue) kitten come from?

Blue is dilute black. The dilute gene is recessive, so two black parents who both carry dilute have a 1 in 4 chance of each kitten being blue.

What colour is the father of an orange female kitten?

Orange or cream, because she needs an orange X from each parent.

Limitations

References

Related reading

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All free tools · By Dr. Zubair Khalid, DVM, MS, PhD.