A guide to cat genetics

I have noticed that when people submit families of cats there tends to be a little confusion about how cat heredity works.



I’ll give you guys the long gist, but my feelings won’t be hurt if you skip to the tl;dr.

Hehe, this is kind of long so I’ll put it under the cut.



A good deal of it is nonmendelean (meaning it doesn’t follow Gregor Mendel’s laws of inheritance, so it isn’t just the easy “dominance/recessive” thing) but fortunately its simple nonmendelean so this shouldn’t be too hard!



Punnet squares ( or punnet square ratios) will be necessary for this (if you want to get the chances exactly right), so I suggest brushing up on it.



This video is pretty helpful: link



This explains it a little, its for elementary schoolers though, I apologize: link



This link provides some practice: link



This Link is fun and provides some practice: link



The ratios are explained here: link



But they are calculated for you here, if you wish to do none of what is above: link

( I will also point out that this cannot do sex linkage or alleles with *subscripts or superscripts )

*a.k.a the second letter I type in 2 letter alleles. (i.e. XOXo, O and o should be a superscripts in this case)





Although they mention dihybrid crosses, it won’t be necessary to do them, merely multiple the fraction of offspring with one trait you want with the fraction of offspring with the other trait you want.



So if you have a ¼ chance at male ginger cats and a ¼ chance at cats with long hair, then you have a 1/16 chance at male ginger cats with long hair.





Several things determine the looks of a cat’s pelt:





Length

Pigment

Pigment Density

Dilution

Agouti

“Agouti Type” + Tabby Type+ Spots

White Spotting



and some other things that effect your kitty as well





Albinism

Pointing

White Masking

Amber



“Curly fur”

Polydactyly

“Ear Deformities”



Short Tails



Dilute Modifier

White Gloving

Tipping/Inhibition (This stuff is usually not too noticeable and almost exclusively found in pedigree cats but here ya go)

Disclaimer: I probably made half these allele symbols up, and may not match actual standards.



Well lets get this show in the road!





~~~Length!



Fur length actually is super duper simple.



Short hair is dominant and represented by L



Long hair is recessive and represented by l





Cats with short hair can be either LL or Ll

cats with long hair are only ll



This works just like the examples up there!

Cats with long hair can be anything from the slightly fluffier kind like the Turkish angora to the fuzz ball Persian.

Note: In both longhairs and shorthairs, they are thinking it may be dominant or at least dominant-ish for cats to have thin coats (think: Siamese). Something to bare in mind.



2. ~~~Pigment!



This gets a little complicated.



To get it first you must understand sex heredity



A female has chromosomes XX, a male has XY



There is almost always a 50/50 chance of male/female offspring.



Now, the pigment genes in cats are the “red” gene (O) and the “not red” gene(o)



Here is where it gets complicated. They are tacked onto the X- chromosome. Therefore a cats color is determines by its sex.



A male cat, will only inherit an X from his mother, while a female will inherit one from each parent. Because a female gets two copies, it can get both XO and Xo, while a male can only get one or the other. This is why only females can be tortoiseshell, because they get both pigment genes and express them.



So if a black momma cat and a ginger daddy cat have kittens, then all the sons will be black, because the only gene they can get from momma is the Xo gene, but all the daughters will be tortoiseshell, due to receiving the Xo from mother and the XO from father.





3. ~~~Pigment Density!



Okay, so out cat has either a gene for red or not red, but what about brown cats?



There is another gene, not located on the X chromosome, that controls what the “not red” gene will be, and only the not red gene. The red gene doesn’t roll like that.



It works similarly to the fur length, except it has 3 alleles (half-genes) to choose from. The alleles are B (black), b (chocolate), and b1 (cinnamon)



Cinnamon is a weird color, so here’s an example of it:



http://wwwdelivery.superstock.com/WI/223/1848/PreviewComp/SuperStock_1848-244299.jpg



But it also isn’t a very common color either



B is the most dominant, followed by b, then b1



Now, just to make sure you understand. A cat can only get 2 or these, or else they may have serious complications.



The combos go as follows:





Cats with Black fur are BB,Bb, or Bb1

Cats with Choclate fur are bb or bb1

Cats with Cinnamon fur are only b1b1





4. ~~~Dilution!



So now we have red, black, brown,ect. But wait. What about gray cats hmm??



Thus we get to Dilution! Dilution, well, dilutes the pigments!



This is a recessive trait.





A “normal” (black, ginger, ect.) cat will be DD or Dd

A dilute cat (grey, cream, ect.) will be dd.



When Diluted the 4 colors transform as follows:





Black-> Grey

Chocolate-> Lilac (Light/dull grey, sometimes slightly reddish) -> unusual outside of pure breeds

Cinnamn-> Fawn (pale reddish-brown or tan) -> unusual outside of pure breeds

Red-> Cream/Golden/Light Ginger

The ones found in pure breeds will not be found in their purest forms in warriors, and may be called by their names in parenthesis if used, if they are even noticeable different.



5. ~~~Agouti

Agouti basically means that the cat’s fur is “ticked”, meaning has colored bands, which is the cause of all tabby patterns.



Some colors ONLY come in Tabby.

Red, Cream/golden, Silver, and Brown only come in tabby.

(Also note, there are two types of brown. Chocolate, and Brown/Dark brown. Chocolate tabbies have dark brown stripes and have the “chocolate” gene for dilution, Brown tabbies have black stripes and have the “black” gene for dilution. Both are usually just called brown and usually show up as, well, brown.)

(Silver tabby also only shows in tabby. There are no solid silver cats (Unless you count black cats) .It is really weird and goes back to the tipping/inhibition stuff, but I did a little more research since its popular, and it turns out it is dominant. Thus one or both parents would need it.)

(Reds/creams only come in tabby because the non-agouti gene doesn’t effect red cats. Through careful breeding, there are “solid” reds and creams though.)



The base part of Agouti is fairly simple, Agouti is dominant to nonagouti so





Agouti is either AA or Aa

Non-Agouti is only aa



Non agouti cats appear solid, although technically no cat truly is, and even black cats can have “phantom stripes” if hit just right in the sunlight.

Note: Agouti cats will appear to have an “M” on their forehead. The only exception to this rule is toygers and some wild-domestic hybrids.



~“Agouti Type”

In addition to agouti, it can come in three different patterns. Abyssinian (rare outside house cats), Tabby (most warriors), and Spots (rare, and this does not include leopard-like rosets and other wild-domestic hybrid patterns those are weird im not even touching those).

This is tougher then originally expected buckle up.

First, you need to figure out if the kitty is “ticked” or not. Ticked means to have the Abyssinian pattern btw.

Ticked is Dominant to non Ticked

Ticked: Tata and TaTa

Not Ticked: tata

If your cat is ticked, stop there. If not, prepare yourself for round 2.

~Tabby Type

Next, you need to know if it is Mackerel or Classic. Mackerel is tiger-y stripes, Classic is big blotchy swirly ones. Classic is pretty uncommon in most of the world, spare some places like parts of Britain where the pattern developed.

Mackerel is Dominant to Classic So:

Mackerel: McMc or Mcmc

Classic: mcmc

Okay so that’s all figured out. Now, what if you want a spotty cat?

~Spots

Spots arise from modifying the already present Mackerel or classic tabby. It “breaks it up” into spots or dashes, bigger spots on classic and smaller on Mackerel. Because of this “breaking up” thing, its often called Broken Mackerel (and I assume Broken Classic for that variant).Spots are very uncommon, and probably won’t be often seen in a warriors setting even if it is dominant.

Spots are dominant so here we go:

Spots: SpSp or Spsp

Normal Mackerel/Classic Tabby: spsp

6. ~~~White Spotting

Now, white spotting can be quite loosey goosey on appearance, and simplified the genes for it can only determine the potential for the amount of white present on the cat.

The alleles for this are equal, so they kind of blend together.





A cat with no white on them is most likely a ss.

A cat with low grade white spotting (white paws, white chin, white spots on belly or chest, and/or white tail tip, so mostly color. aka. < 40% white) is most likely a Ss.

Medium grade is, well, the median between the others, and they can overlap quite a bit. It is possible for either Ss or SS.

A cat with high grade white (very little color, most likely on tail, back, head, face, and/or stray spots, aka. >60% white) is most likely an SS.



SS cats can be pure white. Ss can be completely colored (but the white will still be in their genes or in less noticeable chunks).



A cat with white on them has a chance at blue eyes, and it only increases as the amount of white does too.

Cats with with white spotting are also candidates for odd-eye heterochromia, but it is very rare.



—Other—



1. ~~~Albinism!

Although I advise against making albino ocs I might as well explain it.



An albino animal lacks the ability to make pigments, and therefore appears white with blue or red eyes.

Two different types of Albinism control this, red the most recessive of all 5 albinism alelles.

So a blue eyed albino will be: caca or cacr

a red eyed will only be crcr

Throwing in a C (normal), cscs (siamese point) or cb (burmese point) will null albino always. ( think of it this way: C->cs,cb->ca->cr , Normal-> Point-> Blue Albino-> Red Albino)



But also remember, the ca/cr alleles are pretty rare. Which is why we don’t have as many albino cats as long-haired cats.



But it is also a hamper on a cats survival as well, causing many skin and eye disorders that would make it difficult for a warrior to be anything but one of the early elders.



2. ~~~Pointing!

Although pointing will be extremely uncommon unless one or more kittypets with the same pattern in the area has escaped or been abandoned, then contributed to a clan’s gene pool, I’ll go ahead and explain it anyway.



Pointing in itself is a variation of the Albinism gene called Heat sensitive Albinism. The farther a cat’s body part is, the cooler it is, and the more pigment is produced. More pigment is produced in the extremities because near the warm part of the body, the heat denatures, or turns off, the enzymes used to make fur pigment, because it is heat sensitive.



Now, kittens with pointing are born white, because they are kept equally warm in the mother’s womb, and as they grow their true colors begin to show.



Now, there are three versions of this derived from two alleles. Siamese (cs) with high color contrast, and Burmese (cb) with low color contrast.





Siamese (high contrast, or nearly white plus a dark color) can only be cscs

Tonkinese (a median between the two) can only be cscb

Burmese (low contrast, barely visible difference between pointing and main color) can only be cbcb

It can also occur that a point cat carries albinism, in which case they may be higher contrast then usual, usually you see this in siamese point causing what is called Bondanese (csca)

Now, although it would be tempting to make a Siamese cat go off and join some warriors, I do not recommend it. They have thin coats and are prone to blindness, crossed eyes, and heart problems. Lots of pure breeds have this same problem with their inbred health issues.

But luckily there are sturdier cats who have the same pattern, such as the color point shorthair.

(oh flame points my one weakness)



3. ~~~White Masking!

Once again a simple one. White masking does pretty much what it says it does. It masks all other fur pigments with white, but its genetics are still there and can have colored kittens.



This is actually a dominant allele W, and a normal cat has the recessive w.





White will be WW or Ww

Colored will be ww



This allele is uncommon, which is why the world isn’t over run by white cats.

These cats can have blue eyes and heterochromia as well.

This is also the white associated with deafness, so blue-eyed whites beware! Even odd-eyed whites beware, the ear on the side of the blue eye can be deaf!

4. ~~~Amber



Now although doesn’t occur outside of Norwegian forest cats, so it is incredibly rare to have, it might be able to occur with in a warrior with a smidgen of norgey kitty pet blood!

This color is weird, so here’s a lovely amber tabby!

Its symbol is E and it effects the amount of black pigments shown in the fur, reducing it to the “stripe bands” on the hairs, giving it dark cinnamon stripes but a red-ish colored background.

A cat is “normal” if: EE,Ee

so a cat can be Amber if: ee

The only known colors it effects are Black and Grey.

Black-> Amber

Grey-> Light Amber

But bare in mind, this color isn’t allowed even show cats, so it is going to be very rare if not confusing to warriors.

But in additions to that, the Norwegian Forest cat breed is pretty sturdy breed as long as your clan isn’t in a hot climate where the poor fluff balls could over heat!

Another thing about them, similar to how Point cats are born white, Amber cats are born Black/Grey and their color gradually begins to show as they mature.



5. ~~~“Curly fur”!



There are many variants of “curly fur”. some are recessive, some are dominant. Find a curly haired kitty, look at its breed’s name, find it here, and good luck.





6. ~~~Polydactyly!



Polydactyly occurs when a cat has one or more extra toes on a paw or paws, the front paws usually having 5 each and the back usually have 4 each. Its actually a dominant trait, and usually does not harm the cat and may even aid in grasping and dexterity.



So simplified:

a cat with Polydactyly can be or PP or Pp

A normal cat will be pp



This is very common, especially in the North Eastern US and the UK.

7. ~~~“Ear Deformities!”

The two “cute” ones (folds and curls) are both dominant traits. So:

a cat with folded or curly ears can be or FuFu/CuCu or Fufu/Cucu

A normal cat will be fufu/cucu

But, YOU DO NOT WANT TWO CATS WITH FOLDED EARS BREEDING. IT CAUSES DEAD KITTENS AND/OR CARTILAGE DEFECTS.

That being said, Scottish folds won’t do too bad in clan life, as they have had to mix out of breed to insure healthy litters. American curls are healthy as far as I know too.

8. ~~~Short tails

Tailless-ness and tail shortness is a funny thing. It has three confirmed mutations, but within the three groups cats with different backgrounds display different traits in regards to their tails! It would be a good idea to investigate the breed origins for your cat before jumping into this.

-There is Japanese Bobtail (the same inheritance as Karelian bobtail), which is a recessive trait. This is also the bobtail found in Pixie bobs and American Bobtail.

jbjb- short, curled tail

Jbjb, JbJb- normal tail

-There is Kurilian Bobtail, which is incomplete dominant. I think its only found in that particular breed, so isn’t very common. Their tails are very bunny-like.

kurkur- normal tail

Kurkur- short tail, may or may not be curled

KurKur- short, curled tail

-The Manx tailless/bobtail gene is dominant, seems the most common, and has a lot of variations. It is found in Cymric as well. Its thought to be linked to skeletal problems in them giving it a bad reputation for killing all manx kits who get two copies of the gene. This is called “manx syndrome”, and fortunately its getting rarer and rarer! Cymrics kind of get a double dose of this, and often their kittens die days after birth from being unable to defecate.

MM- Tailless, kills manxes in utero

Mm- ranges from no tail to short tail

mm- normal tail

Cats with no tails from birth tend to live normal, happy lives and don’t have balance issues!

9. ~~~Dilute Modifier

Dilute modifier, you guessed it, modifies the color of dilute cats!

It makes their coat browner, often described as “biscuit colored” or “caramelized”

Its a simple dominant trait, with the symbol Dm.

A cat with the dilute modifier will be DmDm, Dmdm

A cat without if is dmdm

But, a cat with DmDm or Dmdm will not show it if they are not dilute.

The colors go like this:

Blue/Grey-> Caramel

Lilac-> Taupe

Fawn-> (theoretical fawn based caramel. Not seen yet)

Cream-> Apricot

This hasn’t really been seen outside of a few oriental breeds from what I’m finding, and in some places isn’t considered a color.

10. ~~~White Gloving

Outside of white spotting and epistatic white there are a few other genes that will give a kitty white on them, although they are much less common than the other two and also more breed-restrictive. This is the most interesting one to me, which is why I chose to mention it here. It also seems to be the only one confirmed as of now.

It is a recessive gene. Hehe, that’s what makes it interesting! Unlike other white causing genes, this one can be carried!

A cat without the gloving gene is NN or NG (idk why both are capital. w/e science)



A cat with the gloving gene is GG

Although not common, it does pop up a lot in pure breeds!

It was discovered in Birmans and some how made its way to Ragdolls, Egyptian Maus, Exotic Shorthairs, Maine Coons, Manxs, Seychellois, Siamese, Siberians, Sphynxes and Turkish Vans. (copied/pasted almost directly from messybeast, not typing that shit man)

BUT MORE IMPORTANTLY its what CAUSED snowshoes to be a thing. Two siamese with gloving reproduced and voila cute white feets. They were crossed out with domestic shorthairs, giving them the white masks and their cobbier bodies. So you can thank this for the mere existence of grumpy cat.

This trait is p hard to deduce. Breeders generally send in a genetic test to find out if their cat has it, since it can be just as easily caused by low grade white spotting that didn’t show up the generation before. And like in snowshoes, both gloving and white spotting can be present.

———–



Well, that is the end of this guide! Thank you for reading.



I direct any questions about eye color to the cat coat color guide chart as cat eyes, like people eyes, have unpredictable heredity unless you are willing to do all the refraction, intensity, ect shenanigans. These colors listed with the pelts are common in the color, but can have any color listed here really as long as it isn’t the blue or blue-green ones. Those are the only ones where coat color actually matters. Also Green and Hazel are the most common eye colors, Hazel more common then Green on tabbies.



If you have anything to add or if you find a mistake, don’t hesitate to leave an ask!



—————————-



tl;dr



Honestly this doesn’t matter that much and I’m just being a picky butt.



As long as your two ginger cats don’t have a pitch black kitten with blue eyes I can’t really complain. I’m not going to ask for their whole family’s genotypes, just for their heredity to make a grain of sense.





There are more cats with short then long hair

Boy’s colors come from mom, girl’s colors are a combo of mom and dad. I advise reading the long version its weird.

Cats are more likely to be black, then chocolate,then cinnamon

You are more likely to have black cats then grey cats.

Most cats are tabby.

Abyssinian are rare outside of cat shows, stripes are most common, spots kinda rare-ish too, and the leopard-y rosettes and clouded-marbledness being hecka rare.

Red,cream/golden, and brown only come in tabby outside of cat shows.

Tiger-stripes are more common then swirls.

Its common for cats to have a little white on them

Avoid albino cats

Cats with darker tips are unusual, but if your warriors have kittypet ancestry somewhere it wouldn’t be unheard of. Just remember they are born white, and the color changing kitty could be quite a shock to an unprepared clan.

There is a dominant white gene, but it is uncommon.

Amber kitties are extremely pretty, but also extremely rare.

Cats with curly fur look funny and are a bit of an oddity.

A lot of kitties have extra toes.

Curls and Folds won’t be to abnormal if those breeds have mixed in with warriors.

Tailless cats are uncommon and some breeds are very unhealthy. Depending on the setting, they may be more common (such as in Japan).

I’d keep dilute modifier to kittypets.

maybe white feets?

And once again: link