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Fur Color Genetics

2K views 11 replies 5 participants last post by  catobsessed4 
#1 ·
I was reading another thread that got me interested in this.
So I'm wondering...how is it possible for an orange tabby mother to give birth to a pointed cat like Stormy? She had 3 orange tabby brothers. No idea who the father was. :?
Justin's mommy is black and white, so that's a little easier to figure out. :) (Speaking of her, she was finally caught after MANY litters of kittens, allowed to her have last litter, spayed and returned back to her colony.)
 
#2 ·
Well..... it's possible because some genes mask others. (on a side note, it's very interesting that all of the boys were orange tabbies... the father's genes for coat color didn't affect them at all, because the orange tabby gene is on the X chromosome, which they get from the mother)

OK, so back to the subject... Stormy has the orange tabby gene on one of her X's, but she's not an orange tabby because that requires the gene on both X's... basically orange tabby females have to have both parents as orange tabbies (or the mom can be a tortie or calico... but i won't get into that). So, since she only has one orange tabby gene, other genes can mask it, in her case, the gene that gives her the points. So the father probably gave that gene to Stormy. He most likely is not an orange tabby, because if so Stormy would probably have been too, because she would have had orange tabby genes on both X's, and as we see with the boys, if the cat is homozygous (which kinda means "pure") for the orange tabby genes, it masks the other genes. But with just one orange tabby gene, and one gene for who knows what else, the pointed gene masks the orange tabby gene.

(just re-read and realized how confusing this sounds, even to me... and i wrote it! but i can't figure out how to explain it better, sorry... tell me if there's something you need clarification on :oops:)
 
#3 ·
I like diagrams. :D From what you said:

To be orange, female cat must be

X (orange - from mom) and X (orange - from dad)

Stormy is probably

X (orange - from mom) and X (pointed - from dad)

And the pointed overrules the orange. :)

But for males, they are XY, so to be orange all they need to be is

X (orange - from mom?) and Y (anything! - from dad)

So all they need is the orange gene from the mom and POOF orange cat. Us females, we're trickier and more complicated. :p

I'd be interested in seeing how all the color genes releate to one another.
 
#5 ·
KittyEnvy said:
I like diagrams. :D From what you said:

To be orange, female cat must be

X (orange - from mom) and X (orange - from dad)

Stormy is probably

X (orange - from mom) and X (pointed - from dad)

And the pointed overrules the orange. :)

But for males, they are XY, so to be orange all they need to be is

X (orange - from mom?) and Y (anything! - from dad)

So all they need is the orange gene from the mom and POOF orange cat. Us females, we're trickier and more complicated. :p

I'd be interested in seeing how all the color genes releate to one another.
Yup, that's pretty much it! The only thing that wasn't quite correct (and I wasn't clear on) is the pointed gene isn't sex linked; that is, it isn't on the X chromosome. So that diagram should be:
Stormy is:
X (orange from mom) and X (anything from dad)
and pp (pointed - from mom and dad)

Pointed is a separate gene, and I believe it's recessive. So both mom and dad had to give her the pointed gene... it just didn't show up in mom because the orange tabby gene masked it.

(sorry to be even more confusing :D)
 
#7 ·
tammy said:
I read somewhere that one litter can have more than one father. I forgot what the term was. If that's true, that would explain why sometimes the kittens don't look anything like each other or the mother.
Yup, that is true. In Stormy's case, it could be either way - same father or different. Even the four boys who look alike could have different fathers, because they got the orange tabby gene from mom! Strange, isn't it?
 
#8 ·
I just watched something on Discovery about this topic. Basically it said that the genes which determine coat color are triggered at random. They were talking specifically about cloning cats and said that a clone's coat can be different from the original cat’s because of this. They didn't mention any specifics about mother and father genes directly determining kittens' coats. They made it sound like it was all a game of chance based on the genes.
 
#9 ·
That's interesting. I read something about black and white cats... well, specifically white cats with blue eyes, called "The Pigment Parade" - let me find it online - ok it's http://home.earthlink.net/~featherland/off/white.html - but anyway, it's a VERY interesting article about how the cats' genes are expressed during embryo formation. Or at least that's part of the article.
 
#10 ·
Gotcha. I understand basic genetics and all...I guess I just would have thought that orange tabby would be dominant over white. Because white is generally recessive (or at least I think it is?)
Anyway, it's an interesting topic to me!
 
#11 ·
Oh yeah and to make it more interesting, I was told at a cat show (she was in the household pet division) that she was a tortie point, not a chocolate point like I had thought.
 
#12 ·
That's cool too... a tortie point would make sense... torties are when you get:

X (orange - from one parent) and X (black - from the other parent)

So Mom gave the orange gene, and Dad gave the black gene, and then when you combine that with both parents giving the pointed gene, you get a tortie point!
 
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