Ferret Coat Genetics

Agouti/Solid/Self

All ferrets in Australia, as far as I am aware, are Agouti, which is referred to as the `A` allele. Agouti ferrets have different colours in the hairshaft, where the base is lighter in colour and the tip is darker. These are the typical 'polecat' or 'sable' looking ferrets you see. In Australia, it is safe to assume all ferrets are double agouti; `AA`.

In the UK and the states, they have Solid `a(s)a(s)` and Self `a(a)a(a)` ferrets. These are nearly entirely the same colour all over.

There is a hypothetical but unproven theory of a recessive `a` gene. It has yet to be observed but cannot be disproven entirely.

Black/Brown/Champagne

All ferrets, no matter their colour, will either be black-based(`B`), chocolate-based(`b`), or champagne-based(`b(c)`). Yes, even a fully white ferret will carry these genes hiding underneath!

Black ferrets are very common, as this gene is the most dominant. However, not all black-looking ferrets are 'black', as this is dependent on the Extension gene, which we will talk about soon.

Black is dominant to chocolate, chocolate is dominant to champagne, champagne is recessive to both black and chocolate.
`Bb` is black-based carrying chocolate: black, black-sable.
`Bb(c)` is black-based carrying champagne: black, black-sable.
`b_` is chocolate with an unknown second allele: choc, choc-sable.
`b(c)b(c)` is champagne.

Full Colour/Siamese/Albino

This gene is responsible for determining how much colour is on the animal. `C` is full colour, meaning the maximum amount of colour is displayed. It's the most dominant on this allele.

Next is the siamese allele, `c(s)`, also known as 'point'. It's recessive to full colour. It puts the majority of the colour around the legs, arms, head, and tail of the ferret. This may sound confusing, as a lot of ferrets look like they have this pattern, but this is due to the agouti gene and how it expresses on the body. A true siamese/point will have barely any colour on the body and darker colour around the extremities. This colour is not commonly bred nowadays, but can be found in some Australian ferrets.

The most recessive gene on this chromosome is the albino gene; `c`. It removes all pigmentation from the ferret completely, which is why they have pink-red coloured eyes; that is their blood/tissue showing, rather than the pigmentation seen in non-albino ferrets.

A ferret with the genes `CC` is full colour homozygous: black, choc, sable. All offspring will be full colour.
A ferret with `Cc` is full colour carrying albino: black, choc, sable.
`c(s)c` is siamese/point carrying albino: black point, choc siamese.
`cc` is albino or red-eyed white(REW).

NOTE: Albino ferrets are more prone to eyesight issues, sunburn, and skin cancer.

Dilution

Most animals have a 'dilution' gene, which causes them to become grey in appearance, referred to as 'blue'. It was initially believed that the champagne gene `b(c)` was this dilute gene, but then we noticed this colour variation (being a champagne ferret) was not as rare as a dilute+chocolate, referred to as 'lilac', as double recessive colours are far rarer than a single recessive.

Ferrets thus far have not shown colours similar to animals that are confirmed to have the dilute gene, such as dogs, cats, and rabbits. Whilst we cannot confirm it's nonexistence, we cannot confirm it's existence either, so it is often ignored when it comes to ferret genetics.

Dominant Black/Extension/Nonextension

`E(d)` is the most dominant allele within the extension alleles; dominant black. It shows as a deep, dark colour of the fur. For a ferret to be a true 'black' and 'choc', they will need this gene. A majority of backyard breeders claim they have dark or black ferrets when they actually have an 'extension' ferret, not dominant black.

`E` is the extension gene. A majority of ferrets in WA have this gene. It's what creates the appearance of the typical sable, where the darker parts of their fur have a slightly brownish tinge. There is only a very minute difference in colour between a black-based sable and a choc-based sable that has the extension gene, so they are often lumped together as 'regular sable'.

The most recessive gene in this allele is the nonextension gene: `e`. It is what creates the 'cinnamon' ferret, where they have light brown fur. Cinnamons appear 'paler' than a chocolate ferret. Despite this ferret looking choc-like in colour, the standard cinnamon ferret is black-based. A choc cinnamon is even lighter in colour than a choc or a cinnamon.

`E(d)E` is dominant black carrying extension: black, choc.
`EE` is extension: sable.
`ee` is nonextension: cinnamon.

Dominant White

This gene is responsible for dark-eyed white and marked white ferrets. It is dominant and only has 2 alleles, `W` and `w`, so either your ferret has it or it doesn't, and it's very obvious!

The `W` allele is what is referred to as 'homozygous lethal'. This means that if the ferret has two dominant white alleles, `WW`, which only occurs from breeding two white ferrets, they will die, either in utero(in the uterus) or shortly after birth.

`Ww` is a dark-eyed white or marked-white ferret.
`ww` is a non-white ferret, excluding albinos.

NOTE: Dark-eyed white and marked white ferrets are more prone to Congenital Sensorineural Deafness(CSD).

Piebald(Mitt/Milkmouth/Blaze/Panda/Striped)

This gene is rather tricky and has a few variations. Not a lot of studies can determine the exact order of dominance, as not enough ferrets with white markings are bred to others with white markings. As such, there is a debate within the research community whether or not this allele is considered double recessive, where two genes are required such as `s(b)s(b)`, or incomplete dominant, where the white markings show even if the ferret has a dominant and recessive gene, such as `Ss(p)`.

The only thing determined about this locus is the following:

`S` is the most dominant allele, where the ferret has no white markings. This doesn't include: milktoes, knee patches, or bibs.
`s` is the second most dominant, being 'mitt', where the ferret has white socks on all feet.

After these, the order of dominance is murky and undetermined:

`s(m)` is milkmouth, which appears as white around the mouth. As far as I know, it has not been seen in Australia, or at least not in WA.
`s(b)` is Blaze, where the ferret has a white stripe along the top of their head.
`s(p)` is panda, where the head and upper body is white, much larger than a typical ferret 'bib'.
`s(s)` is striped, which is actually believed to be another name for 'marked white' where they have a dark stripe along the spine down to the tail. This allele can be excluded from most gene tracking.

NOTE: Ferrets with mitts are more prone to Congenital Sensorineural Deafness(CSD). Blaze and Panda ferrets are more prone to Waardenburg Syndrome.

Roan

The roaning gene is what creates Silver and Black Roan Mitt ferrets. It is referred to as 'incomplete dominant', which means if a ferret has 1 roan gene, `Rnrn`, it will show as silver. If a ferret has 2 roan genes, `RnRn`, it will appear more silver-looking than the ferret with only 1 roan gene.

It is also believed that the Piebald gene is linked to a ferret being silver, as all of them have some form of white markings, such as mitts or blazes. There is a lesser known theory that the Progressive Greying locus is also linked to silver ferrets, but this has less evidence to back it up.

`RnRn` is a ferret with homozygous roan alleles, meaning it appears more silver than a heterozygous roan ferret.
`Rnrn` is a heterozygous roan ferret, which appears silver.
`rnrn` is a ferret without roaning and would not appear silver.

NOTE: Ferrets with roaning are more prone to Congenital Sensorineural Deafness(CSD).

Progressive Greying

This is a lesser known dominant gene, `G`, where a young ferret starts out fully coloured, and as they age, they gain more and more white hairs as time goes on. It is also proposed to be incomplete dominant, where a ferret with double greying, `GG`, would grey at a faster rate than a ferret with a single greying gene, `Gg`.

This gene is potentially linked to silver ferrets, but is not fully confirmed.

`GG` is a ferret with a large amount of greying, where their fur slowly gains lighter hairs over time.
`Gg` is a ferret with greying, where their fur slowly gains lighter hairs over time, but not at the same rate/speed as a homozygous greying ferret would.
`gg` is a ferret without greying hairs.

NOTE: Ferrets with premature greying are more prone to Congenital Sensorineural Deafness(CSD).

Milktoes

Whilst not given a specific allele, milktoes may trick people into believing their ferret is a mitt. On average, milktoes vary in size when being recreated on offspring; sometimes it's only 1-2 toes, other times it can be the entire paw. The easiest giveaway is milktoes are often asymmetrical with the hind feet.

This isn't specifically linked to any gene in particular, but shows a lot of inheritance potential. We are currently working under the assumption that milktoes are dominant, as they have only appeared in kits from parents who have milktoes. It does not currently show any signs of being sex-linked.

Bibs

Ferrets often have a large white 'bib' shape under their chins. Some ferrets may only have a small white mark there, or no bib at all!

This isn't specifically linked to any gene in particular, but shows a lot of inheritance potential. We are currently working under the assumption that bibs are dominant, as they have only appeared in kits from parents who have bibs. It does not currently show any signs of being sex-linked.

Knee Patches

If you look at a ferret's knees, some may have round patches on them. Others don't, or maybe they only a few little white hairs visible. It's suspected knee patches may be linked to bibs, but currently this isn't confirmed in any documented studies.

This isn't specifically linked to any gene in particular, but shows a lot of inheritance potential. We are currently working under the assumption that knee patches are dominant, as they have only appeared in kits from parents who have knee patches . It does not currently show any signs of being sex-linked.

Mask/Hooded/V

The shape of a ferret's mask changes depending on what line your ferret is from. Aside from the typical 'mask' a ferret has that covers their eyes like a burglar's mask, they also can be hooded, where the colour extends up to the top of the head. Another known variation is the 'V' mask that looks like a V, extending down the ferret's nose.

This isn't specifically linked to any gene in particular, but shows a lot of inheritance potential. Order of dominance is not currently confirmed, but being observed, recorded, and interpreted.

Belly Marks

Occasionally, ferrets have little white spots on their bellies. Whilst having these marks technically makes them a 'harlequin', they're still a unique feature!

This isn't specifically linked to any gene in particular, but shows a lot of inheritance potential. We are currently working under the assumption that these marks are recessive, as they have appeared in kits from parents without these spots. It does not currently show any signs of being sex-linked.

Dark Nose/T/Speckled/Pink

The classic black ferret will also have a dark black nose. Not all do, but they often go hand-in-hand. Some noses will have a 'T' shape on them. Others will have tiny little black spots here and there. Or, most common, you'll have a ferret with a completely pink nose! Just be aware: pink noses can burn easily in the Australian sun.

This isn't specifically linked to any gene in particular, but shows a lot of inheritance potential. We currently believe that T noses are dominant to pink and dark noses and Speckled is either dominant to all or recessive to all. More research is required.

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