Cat Genetics Question

[haleyds]

Hi all,
So as most of you that frequent this thread know that I too frequent it lol. I am fascinated by cat color genetics and love learning new things from the rest of you guys. I'm a huge science nerd so finding out where colors come from and what gender/breeds they're linked to is just amazing.
Anyway, something I've not really figured out is where the calico gene comes from. I understand that boy kittens inherit their color from the mothers and females get a gene from both mother and father. So how is a calico produced? It's fairly common here in America but I know many people from London/Europe that hardly ever see the color. And when a mother cat is a calico what will her baby boys look like since males cannot be calico but they still technically speaking get their color alleles from her??
Sorry for so much, I'm just really curious to know how that works lol.

 

[StefanZ]

What I understand, its really just the red which sits on the X-kromosome. And thus, red boys get red from momma, but red girls can get it from either parent.

Other colors can sit on other kromosomes.

If Im mistaken, so be it, even if its somewhat embarrassing. .

 

[abyeb]

I think it's something like this...

Calicos and torties need both the alleles O (coding for orange) and o (coding for not orange). These sit on the X chromosome, which is why a cat needs two X chromosomes to be able to be Oo. That's why 2999/3000 calicos and torties are female (XX). The only case where a male calico or tortie can be born is if they inherit XXY (known as Klinefelter syndrome in humans), which is why male torties or calicos are usually sterile.

 

[GemsGem]

This is the way I understand it - I could be wrong

Cats have two sex chromosomes which determin what sex they will be
Females are XX and males are XY

Red and black are dominant colours and are only carried on the X chromosome.

So, males only have one X Chromosome - so, can only inherit either Red or Black not both

Females have two X chromosomes - so, can inherit two red, two black, or one of each

 

[StefanZ]

Aha. so its as I though, but its both red and black on the X - kromosome. So black males cant get black sons either, unless momma helps out.

 

[haleyds]

Awesome awesome! That makes sense!

 

[1CatOverTheLine]

.
Hopefully this won't be seen as being too basic; there's a brief, simplified article on calico genetics here:

The Genetics of Calico Cats

.

 

[raysmyheart]

Wow! I can't post photos because I do not have a camera, but my Speedy is Siamese-calico mix! She has the blue eyes, if you look at her whole body she is definitely Siamese, but her face is mostly calico, with the Siamese features starting at the forehead and up. I am going to read the article about calicos. This is a very interesting question.

 

[kashmir64]

If you think this is confusing, just wait until abyeb gets into the dilute torties. Although informative (and thank you for it), it made me pull my hair out in confusing frustration.

 

[KatsPurrrsians]

Very interesting and informative!