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I have a brown (cinnamon) cat, I assume her alleles would be b’b’ and oo. She was bred with either a black male (B_ o) or an orange male (__ O), or both if it’s possible for her to have carried the black cat’s sperm with her for a while until she met the orange cat. I can’t remember how long, I was eight or nine when this happened. She had five kittens, an orange female, an orange male, two black males, and a cinnamon male. From my understanding, it shouldn’t have been possible for her to have two orange kittens, let alone for one of them to be female, with either male. However, I have only taken two genetics classes! So, how could this have happened?


Edit: cat coat color genes: Primary coat color alleles: B- black, b- chocolate, and b’- cinnamon. B is dominant to b is dominant to b’. Orange coat color alleles: O- orange, o- not orange. These alleles are carried only on the X chromosome. If the cat has OO or OY, they will be orange. If the cat has Oo, they will be tortieshell. If they have oo or o, the primary coat color will be displayed.

If my cat (b’b’ oo) mated with the black cat (B_ oY), the kittens should have been 50% black and 50% dependent on the second allele of the male, either black, chocolate, or cinnamon. None should have been orange. If my cat mated with the orange cat (_ _ OY), the kittens should have been 50% non-orange males and 50% tortie females. None should have been orange. I’m unsure about the black cats’ statuses as tabbies, as it can be hard to tell, and the black cat was a stray that we don’t have photos of to even try to check, but the brown cats and orange cats were all tabbies. None were dilute, none had white patches, etc. It is possible for cats to be intersex and for this to affect their coloration (XXY is how we get male calicos and torties), so perhaps the male orange kitten was OoY, but that would have made him a tortie. For there to have been an orange female or orange XXY male they would need two ‘O’s, which would not have been available to them. Or perhaps the female was just O? But I feel like the odds of there being two intersex kittens in the same litter must be very low. Plus, she had no other physical anomalies (she went thru a series of tests including ultrasounds, x-rays, and a CAT scan to diagnose a well-hidden tumor later in life and nothing strange came up internally either). The orange tom could not have been XXY, as this causes cats to be sterile. Also, the only mutations I have found that causes oo kittens to be orange also tend to cause a shift in coat color during kitten-hood, which none of the kittens experienced.

My cat: My cat with the orange female and short-haired black male: The orange female grown up: The orange male grown up: One of the black males: Here is that same black male grown up, he’s the only one of the family with long fur! Here is the other black male, you can see the stripes on their legs a bit as babies, not so much grown up: The brown male: And lastly, here is my cat and her brother as kittens, you can see he also had faint stripes. All of the kittens in their litter looked like either one of them and their mom was brown as well: I don’t have pictures of either toms, one was a stray and the other was a farm cat. I do have a picture of my cat's mom and her litter if anyone is interested in that.

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    $\begingroup$ What breed of cat did you have? $\endgroup$ Sep 20, 2021 at 3:21
  • $\begingroup$ @classy_BLINK Sorry, she’s an American shorthair! All three of them should be/have been American shorthairs. $\endgroup$
    – jeln
    Sep 20, 2021 at 14:28
  • $\begingroup$ It would be very helpful if you also add her picture in question. $\endgroup$ Sep 21, 2021 at 4:32
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    $\begingroup$ Welcome to Biology.SE. I think you will get a better response if you elaborate on what lead you to your conclusions about your cats genotype (and what alternative genotypes you have considered). As someone with a genetics background, but who isn't current on the genetics of cat coat color (and no time to read up on that) I would personally find it helpful if you laid out the logic of why you think orange kittens are impossible. $\endgroup$
    – tyersome
    Sep 22, 2021 at 17:47
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    $\begingroup$ Cat coat color is controlled by many genes not just two and at least partially environmentally developmentally triggered. so its not entirely genetic on top of being genetically complex. worse some genes are unknown and some other genes are sex linked so will not express in some sexes. $\endgroup$
    – John
    Sep 29, 2021 at 20:29

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If Momma cat is photos 1 and 2 then what you have there is a tabby cat - these have agouti hairs and the Agouti colour alleles. Agouti means that they have bands of colour on the hairs. I don't know if this means that they also carry other colour alleles.

In addition, I believe that cats are superfecundators (fertilization of multiple eggs from separate acts of sexual intercourse), which means that if they mate with more than one male during the fertile period, then they can have multiple fathers for one litter, as is discussed in this article.

So - yes, it is possible that there are more than one father associated with this litter, and that there are some underlying genetics that can also result in this.

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