Some genetics questions about colourpoints/Siamese as well as vestibular disease

CuriousKittens

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Hi there, I have a few genetics questions. I wasn't able to find a suitable forum specific for genetics so I hope it's okay to go under this section. Let me know if there's a better one. My questions are about vestibular disease and about colourpoints/Burmese/Siamese. Some of them might be a bit stupid but my information processing is kind of low right now and for some things I just need a concise confirmation of things (especially since the internet is full of misinformation). Also I'm not great at making things make sense so things will kind of be all over the place, sorry.


1. Obviously not all colourpoints are Siamese, they're just Domestics. But are they all "descended" from Siamese cats/those who became the Siamese breed (even if an extremely long time ago) or can they be not at all related? I guess, would they be genetically linked aside from purely the colour?

2. I know colourpoints are common but typically they are relatively higher contrast. I don't usually see Burmese-type low contrast Domestic colourpoints. Do you? Are they more likely to be more closely related to Burmese cats?

3. Siamese and Burmese cats are more susceptible to vestibular disease. Would Domestic colourpoints also be more susceptible or not?

4. There is vestibular disease that is caused by certain problems (ear infections/polyps, etc.) but there is also idiopathic vestibular disease. Additionally, Siamese cats have been associated with an inherited or congenital form of the disease. Does this mean it's present at birth and permanent? And are they also more susceptible to the idiopathic transient form?

5. And also a more medical question here. If a cat was scratching its ears and shaking its head often for a few days, and then had an onset of vestibular disease but was found to not have an ear infection or polyps or something like that, would the scratching/shaking indicate that there was actually some physical problem in the ear that was missed or maybe was present before? Or would it simply be because of some discomfort even though it not really physical? Or could the scratching and shaking cause vestibular disease?


I think I'm forgetting some questions but I guess I'll start with this. Thanks for any insight or help!
 

Kieka

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1. It might help if you think of being colorpoint as similar to humans being redheaded. You can't be redheaded unless both your parents carry the redhead gene. Which means that anyone who had red hair can utlimately trace their genetic heritage back to the first redhead or the first group of redheads (since it could have genetically occured simultaneously). Similarly no colorpoint can exist without having it in their genetic background. Since the genetic pool that the colorpoint gene developed in became what we know siamese, yes all colorpoints trace back to siamese in one way or another.

2. Actually, they all darken with age so the contrast varies throughout life. The high contrast tends to be something selectively bred for in purebred so you can find colorpoints who get very dark within their lifetimes with the right mix of environmental (more cold exposure) and genetics (reduced heat regulation with age). While you find others that don't.

This is my domestic colorpoint moggy at 8 years old for an example.

20220501_100346.jpg
20220504_123335.jpg


Compared to my 7 year old domestic colorpoint moggy.

20220503_190721.jpg


And both of them 7 years ago.

Screenshot_20220507-200642_Instagram.jpg


3. I don't think we know if colorpoint are more susceptible. Since Siamese and Burmese tend to be, we can probably make the logic link that something connected to colorpoint is. Colorpoint is a type of albinism and hearing problems are fairly common with humans with albinism. Since vestibular issues can be caused by ear issues, it is all interrelated. Going back to the redhead perspective, could be something similar to redheads that tend to have slightly different reactions to anesthesia. But ultimately, cat health and genetic health items are still relatively unknown. So, do we know for sure? No. Can we make an educated guess based on history and observation? Probably. I'd go with it's likely linked to the same gene impacting color so it does make colorpoint more susceptible.

4. I really am not sure. Educated guess, I'd go back to since colorpoint is a form of albinism it would be related to that so in some cases it can be present at birth and permanent.

5. Could be caused by discomfort or could be something missed. I'd recommend finding a cat specialist vet to exam and determine.
 
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CuriousKittens

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1. It might help if you think of being colorpoint as similar to humans being redheaded. You can't be redheaded unless both your parents carry the redhead gene. Which means that anyone who had red hair can utlimately trace their genetic heritage back to the first redhead or the first group of redheads (since it could have genetically occured simultaneously). Similarly no colorpoint can exist without having it in their genetic background. Since the genetic pool that the colorpoint gene developed in became what we know siamese, yes all colorpoints trace back to siamese in one way or another.

2. Actually, they all darken with age so the contrast varies throughout life. The high contrast tends to be something selectively bred for in purebred so you can find colorpoints who get very dark within their lifetimes with the right mix of environmental (more cold exposure) and genetics (reduced heat regulation with age). While you find others that don't.

This is my domestic colorpoint moggy at 8 years old for an example.

View attachment 419530View attachment 419534

Compared to my 7 year old domestic colorpoint moggy.

View attachment 419539

And both of them 7 years ago.

View attachment 419540

3. I don't think we know if colorpoint are more susceptible. Since Siamese and Burmese tend to be, we can probably make the logic link that something connected to colorpoint is. Colorpoint is a type of albinism and hearing problems are fairly common with humans with albinism. Since vestibular issues can be caused by ear issues, it is all interrelated. Going back to the redhead perspective, could be something similar to redheads that tend to have slightly different reactions to anesthesia. But ultimately, cat health and genetic health items are still relatively unknown. So, do we know for sure? No. Can we make an educated guess based on history and observation? Probably. I'd go with it's likely linked to the same gene impacting color so it does make colorpoint more susceptible.

4. I really am not sure. Educated guess, I'd go back to since colorpoint is a form of albinism it would be related to that so in some cases it can be present at birth and permanent.

5. Could be caused by discomfort or could be something missed. I'd recommend finding a cat specialist vet to exam and determine.
1. I guess I was trying to see whether the mutation/allele could've popped up in different places independently but it's probably unlikely.

2. I know they darken and can get quite dark but to me there typically still seems to be a difference. Dark Siamese/colourpoint tend to have a variance in body colour (within the same cat at the same time) that doesn't quite look the same as Burmese which looks smoother. Obviously it can depend on the individuals but still.
Siamese
seal-point-siamese.jpg
maxresdefault (3).jpg
mia_w_ribbon.jpg

Vs Burmese
image (1).png
Screenshot_20220508-091917_Chrome.jpg


Dark-body Siamese would still be cs while a Burmese/sepia would be cb, right? And I forgot to mention, they'd have non-blue eyes. I've managed to come across a few more sepia/Burmese-type rescues/moggies/domestics online so it seems they're there, just not nearly as commonly. Understandable considering Burmese are only about a century old. Can't be sure that they're cb but they have non-blue eyes.

5. I'm not asking for medical advice (don't think we're really allowed to anyway), this happened a while back to a friend's cat and it got me wondering.

I'm doing a case study for school so I'm just curious. Ultimately none of this is entirely necessary for it (the assignment is really small and simple) but I like to be thorough when I can. My friend has a Burmese-type tortoiseshell with pale yellowish/greenish eyes (frankly wouldn't have known she was colourpoint/Burmese if she hadn't said so, it's so hard to tell on Burmese torties for me, though she does look different from a regular tortie). She was a rescue and I always hesitate to say one is a breed or "part-breed" for rescue kitties. Might just fudge it and say she's Burmese if they are also more susceptible to the transient idiopathic vestibular disease.

Thanks for the reply! Still looking for responses from other people if they have anything to say too.
 

IndyJones

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All cats can get idiopathic vestibular disease. Indy has it and she's just an American shorthair mix. I don't think it's specific to any breed, it's just something some cats get.
 
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CuriousKittens

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All cats can get idiopathic vestibular disease. Indy has it and she's just an American shorthair mix. I don't think it's specific to any breed, it's just something some cats get.
I know that, I'm asking whether Siamese and Burmese are more prone to the "regular" transient idiopathic type than other cats, since they're more prone to the congenital form. Being more prone doesn't mean that other cats don't get it too.
 

Maurey

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Burmese and Siamese have different genetics — There are three distinct variations of the CP gene.

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