Tabby cat genetics: Stripes, swirls, spots and ticked coats

Level: School to high school · You’ll need: dominant and recessive alleles and a dihybrid cross · Part of cat genetics

Tabby pattern genetics is a two-step story. First, the agouti gene decides whether a tabby pattern shows at all: cats with at least one A allele are tabby, and a/a cats are solid. Second, other genes decide which pattern it is: mackerel stripes, classic swirls, spots or a ticked coat.

Assumptions for the crosses on this page: the agouti gene (A dominant, a recessive) and the tabby-pattern gene (Mc mackerel dominant, mc classic) are inherited independently, other genes are held the same, and there are enough kittens for the ratios to show.

Step 1: agouti decides whether the pattern shows

Every cat carries a tabby pattern, even a solid black one. What changes is whether you can see it.

• Agouti (A/A or A/a): the hairs between the stripes are banded, with light and dark sections along each hair. The banded background lets the darker stripes stand out. This is a tabby.
• Non-agouti (a/a): every hair is fully dark, so the stripes blend into the background. The cat looks solid. Solid black kittens sometimes show faint “ghost” stripes that fade as they grow.

The gene is ASIP (agouti signaling protein). In solid cats, a small deletion stops the protein from working.

This is a classic example of epistasis: one gene (agouti) controls whether another gene’s effect (the pattern) can be seen.

One exception: orange cats always look tabby

Orange (red) and cream fur show tabby markings whether the cat is A or a/a. The 2025 studies of the Orange gene place it after the step the agouti signal controls, so agouti can’t switch orange pigment off. That’s why you rarely see a truly solid orange cat, and why “are all orange cats tabby?” is nearly always answered yes.

Step 2: which pattern

Tabbies typically share an “M” marking on the forehead, whatever their pattern (it’s faint on ticked cats).

The pattern itself is laid down very early. A 2021 study found that the skin of cat embryos already shows thicker and thinner areas that match the future dark and light parts of the coat, before hair follicles or pigment form.

Worked crosses

Two tabby carriers: A/a × A/a

¾ tabby, ¼ solid black. Check it in the calculator.

Pattern genes in a tabby × tabby cross: A/A Mc/mc × A/a Mc/mc

Every kitten gets an A from the first parent, so all kittens are tabby. The pattern gene gives the usual 3:1: ¾ mackerel, ¼ classic. Check it.

When the pattern is hidden: a/a Mc/mc × A/a mc/mc

Use the product rule. Half the kittens are agouti (A/a), and half of those are mackerel (Mc/mc):

The solid kittens still carry pattern alleles. You just can’t see them. Check it.

Are tabby cats male or female?

Both. The agouti and tabby-pattern genes are on autosomes (not sex chromosomes), so tabbies of every color come in both sexes. The sex link people remember belongs to orange: orange tabbies are more often male because the Orange gene is on the X chromosome (see calico and orange cats).

Common questions

Does a solid cat have tabby genes?

Yes. It has pattern alleles; a/a just hides them.

Is tabby a color?

No. Tabby is a pattern that comes in every color: black (brown) tabby, blue tabby, red tabby and more.

Do stripes on an orange cat show it’s agouti?

No. Orange cats show stripes regardless, so stripes on an orange cat don’t tell you its agouti genotype.

Do spotted and ticked tabbies work like mackerel and classic?

Not simply. They involve other genes and are less well understood.

Practice

1. Two solid black cats (a/a) have kittens. What fraction are tabby (ignoring orange)?
2. A mackerel tabby (A/a Mc/Mc) and a solid black cat (a/a mc/mc) have kittens. What are the expected proportions?
3. Why can a solid black cat be a parent of classic tabby kittens?

Where the model stops

• The calculator models agouti and the mackerel/classic gene only. Ticked and spotted patterns, and the many shades of tabby, aren’t modeled.
• Pattern clarity varies: some tabbies have bold markings, others faint or broken ones.

Related

• Cat coat color calculator: set agouti and tabby pattern for both parents
• Calico and orange cats: why orange fur always shows stripes
• Dihybrid cross explained: two genes at once, as in the third cross
• Beyond Mendelian inheritance: epistasis and other exceptions

Sources

• Eizirik E, et al. “Molecular genetics and evolution of melanism in the cat family.” Current Biology 13, 448–453 (2003). doi:10.1016/S0960-9822(03)00128-3
• Kaelin CB, et al. “Specifying and sustaining pigmentation patterns in domestic and wild cats.” Science 337, 1536–1541 (2012). doi:10.1126/science.1220893
• Kaelin CB, McGowan KA, Barsh GS. “Developmental genetics of color pattern establishment in cats.” Nature Communications 12, 5127 (2021). doi:10.1038/s41467-021-25348-2
• Kaelin CB, et al., Barsh GS. “Molecular and genetic characterization of sex-linked orange coat color in the domestic cat.” Current Biology 35, 2826–2836 (2025). doi:10.1016/j.cub.2025.04.055
• UC Davis Veterinary Genetics Laboratory, Feline coat color.