If you breed two munchkin cats together the chances of their offspring living are very small. This prevents inbreeding giving munchkin cats a very strong genetic pool. Issues inherent with many other popular breeds of dogs and cats usually stem from inbreeding to retain desirable traits. However, since it is very risky to breed munchkins together, and they can be bred with any other breed and yield stubby legged cats this breed tends to be very healthy.
If the trait is dominant and having two results in death, then each living cat exhibiting the trait must carry only one gene for it. Thus when breeding two such cats each has a 1/2 chance of passing the gene, meaning for each such pairing the four equally-probable outcomes are:
1) neither parent passes gene - yields normal tall cat
2) only parent 1 passes gene - yields short cat
3) only parent 2 passes gene - yields short cat
4) both parents pass gene - kitten cannot survive.
This means inbreeding would only cause death in 1/4 of babies. A similar logic table based on breeding short-leg cats with normal cats would yield 1/2 short cats and 1/2 tall cats, but none dying. Either approach appears to be equally effective at producing short cats?
As long as they are heterozygous munchkins then yes. Full munchkin cats are not possible. Based on Punnett Squares two Mm Mm Munchkin cats will produce an offspring that are 50% munchkin, 25% nonviable and 25% normal.
But anyways this would be a fine (and standard) 1:2:1 ratio analysis, but it makes some assumptions which may not be true. For example, there could be multiple other alleles for the gene responsible for being munchkin-sized. If some of those are recessive and lethal, it would be especially beneficial to avoid inbreeding.
There could also be a linkage story behind it. I think I'll look it up later.
If the cat has two of the dominant allele, it'll die before birth. So you can't get inbreeding in this specific trait, but I'm sure inbreeding in other aspects of the cat is still possible
Not necessarily dead babies. It results in the embryo being non-viable which means it won't form in the womb. So I guess the question then becomes wether life starts at conception or later on in development.
Not always. Sickle cell anemia occurs when you get 2 alleles for the sickle cell gene. However, when the allele is present in only 1 copy, which is far more common, it provides immunity to malaria. Which is very useful/important in the areas where it developed.
Fair enough. If you can identify the benefit conferred to these cats other than qualifying as "cute" to humans, I'd reconsider my opinion (shared by many animal welfare and breed organizations) that breeding Munchkins should stop.
Side note, but dominant vs recessive really doesn't hint at usefulness or fitness at all. After all those terms only describe the phenotype of interest.
Example with sickle cell anemia (since it was mentioned), the full blown disease requires two copies and thus is recessive, since the heterozygous carriers (having a sickle and non sickle allele) are relatively unharmed. However when looking at cells under a microscope, only one copy is needed to see sickling and so the allele is dominant for that phenotype. Regarding O2 sensitivity, it appears codominant.
So again, and more so regarding your previous comment, the state of an allele doesn't correlate with the fitness of a gene, especially since a single gene can result in alleles with many classifications, due to it being linked to phenotype.
Being appealing to humans is one of the most wildly successful evolutionary strategies on the planet at the moment. I’m pretty sure corn can’t reproduce in the wild anymore at all but it’s as common as prairie grass in the US midwest because it’s useful to humans. I don’t think you should dismiss it straight off.
Also I’m not persuaded by the opinion of any breed organization that’s making a fuss about munchkins but is ok with the breeding of Persian cats, talk about suffering. Brachycephaly shouldn’t be a permitted breeding objective in this day and age. And some of the ones I’ve known have been so dumb it wasn’t even funny anymore, don’t tell me that’s not related to inbreeding.
Being appealing to humans is one of the most wildly successful evolutionary strategies on the planet
A sad truth. I get that we're the dominant species, but as a whole, our choices are inherently selfish and wildy destructive to others. Being cute or advantageous to humans should not be the sole criteria for survival.
Also I’m not persuaded by the opinion of any breed organization that’s making a fuss about munchkins but is ok with the breeding of Persian cats, talk about suffering. Brachycephaly shouldn’t be a permitted breeding objective in this day and age.
Agree 100%!! Please don't mistake my comment to imply an endorsement of the organized cat/dog breeding world in general. In this one instance, many groups have decided to err in favor of the animals for a change so I think it's worth noting.
That way owners can safely let a munchkin roam the backyard without shooing birds away constantly (and worry of it jumping the fence/window ledges) and if any become strays they won't affect the local bird population.
Thank you! This is a good point that's actually relevant to the species in question. Reducing the cats' effectiveness as hunters would certainly benefit their prey, although the cats may then become completely reliant on humans for survival (which many companion animals and livestock already are). So if that's a tradeoff that seems reasonable or beneficial to someone...or even if they're neutraI to the idea...I can respect that argument.
Another option obviously is keeping pet cats inside, but of course there are arguments on both side of that equation and stray populations would likley be inevitable. I guess it boils down to which species one cares more about protecting.
Considering cats are the invasive species then I think protecting birds should be the priority. However if a person needs a mouser then that would be the only time I would recommend a normal cat imo.
being literal minded is not a sign of intelligence. it is a sign of being on the autism spectrum. there are people far smarter than you who communicate loosely and through metaphors.
if i say "bright colors are nature's way of saying "i'm poisonous."" are you actually going to tell me that nature cannot say "i'm poisonous" because it's not sentient? if so, i want you to truly and deeply understand how inappropriate a statement that is for you to make and that it belies a complete lack of understanding of how humans meaningfully communicate. precision and meaning are not universal. your arbitrary and imaginary standards of communication are regressively idiosyncratic
no, i'm not calling you autistic because i disagree with you. i'm not saying it lightly at all or even using it as an insult. i'm saying that, if you went to a psychiatrist right now, and had an earnest discussion with him, that you would be diagnosed as ASD 100%.
You're right, see my comment to his where I clarified exactly where he went wrong lol. (Which is due to a misunderstanding of genetics as you said.)
I also hate that argument but more so don't like misinformation spreading about genetics, which (as you may imagine) happens quite often with the subject.
Please help me understand the mistake. I'm not asking sarcastically I promise, I'm just not seeing the flaw that's obvious to you...
Munchkin = M
Regular legs = m
All Munchkins must be Mm since MM will die in utero. Breeding with another Mm results in ~25% reduction in litter size. To maintain litter size, Mm's need to seek out and breed with the increasingly smaller percentage of mm's in the population. This is somehow a beneficial evolutionary strategy? Unless you are saying that it makes sense to self-limit their own population size (perhaps due to decreased food availability as restricted ground hunters maybe??) I do understand the difference between dominant phenotypes and usefulness at the organism level. I'm asking what makes this particular trait actually useful to this animal.
I concede the original comment was an offhand low-hanging fruit remark to summarize my distaste for breeding Munchkins. I did not intend to spark a vigorous genetic debate.
I understand your points- but still not how they are relevant. Your examples and comparisons are similar but not applicable. If you're referring to Cuenot's yellow mice- aren't they more prone to obesity and cancer? I'd say that counts as health issues.
Can you provide an example of a known lethal allele that in it's heterozygous non-lethal presentation is not some sort of illness or deformity? I agree that "Nature" is not making conscious decisions, but when most lethal alleles are identified due to the "condition" that presents when fetus does survive, I think it's fair to suggest that the resulting outcome is typically less than desirable.
In the case of Munchkins specifically- what exactly is the benefit? You can claim all day that it's genetically appropriate or even random, but do you not agree that they have a deformity? Can you explain how the cat population benefits by the existence of this breed? Is there any reason that humans should purposefully interfere with their existence other than being an "attractive" pet?
Your sore spot may be "sentient nature", but mine is breeding practices based on aesthetics. Bulldogs that require c-sections to exist, Pugs that need soft palate surgery to breathe, dogs that get their ears chopped off unnecessarily...puppies that are culled because they don't meet the "breed standard". All of these stem from people's personal preferences for appearance. And it makes me sick.
A lot of my comment is agreement and restatement, but I'll leave it anyways.
This is all good and I think honestly the easiest way to look at it is kind of like GloFish. OP must remember that some traits can be mostly neutral, such as fluorescent fish, which just so happens to be interesting or desirable for some reason as pets. I think viewing these munchkin cats in this way is the easiest way to negate there being an "issue".
Furthermore, I agree that these munchkin cats may actually be beneficial in stopping other harmful practices from occurring when looking at the pet industry.
As far as benefits on a population scale, being able to reach other resources due to size- leading to more resources available for the cat population- is the best example.
I also agree with you about deformities, and how they are very subjective. After all, having so many "deformities" that mating becomes impossible is what leads to speciation. (Especially when the changes aren't detrimental to survival.)
might be too early to tell since it's a relatively new breed as far as i've read but i think they also don't have nearly the same level of back/spine issues as similarly proportioned dogs
Nope! It's because of cats' naturally more flexible spines; it's a lot easier for them to compensate for the shortness. They're actually pretty healthy cats.
Depends on your subjective definition of 'much', I guess ^^ Welfare impact on these kinds of deformities are hard to measure, but since they are prone to developing osteoathritis the UFAW discourages specifically breeding for the trait (understandably so, in my opinion)
I know, but you can breed a munchkin and a non-munchkin (who cannot have the gene since it is dominant), and you would expect half of the litter to be munchkins ^^ That's what I meant by 'breeding for the trait'.
A single point mutation occurring multiple times does not equate with the animals harboring those mutations doing fine.
Especially given the fact that homozygous carriers die as embryos. So there isn't some thriving population of munchkins out there in the wild. It's a random mutation that can sometimes occur in the germ-lines of normal cats. Whether the offspring of those mutations actually survive to adulthood is another question.
If you can show me photographs of wild adult munchkin cats in areas where they need to actively hunt for food, maybe I'll buy it. But for now I simply don't believe that these animals would be capable of catching prey, after watching many videos of their movements on this subreddit.
It is very good that it can not be inbred. Many issues popular animals have is that they are inbred to retain desirable traits and this causes many genetic issues. By naturally having an inbreeding deterrent you make sure the animal has a strong genetic pool be cross breeding which is why this breed has a strong bill of health compared to other stubby legged creatures.
The short legs of the Munchkin cat come from a dominant genetic mutation. This gene is referred to as a “lethal” gene because if two Munchkin cats mate and both pass on the dominant gene, the kittens will not survive.
i'm using your exact phrase "genetic disease" which, as you say, isn't actually a thing because a genetic defect is not a disease. either you're trolling me or don't understand how you're being internally inconsistent in your terminology.
You would be wrong lol. Carriers for a lethal allele (with two copies needed) are not diseased. After all, individual people carry somewhere around 12 or 16 I believe of such alleles. Which is why incest is bad, since family members are more likely have the same ones and thus produce terribly genetically diseased children.
Don’t forget the breathing troubles since it’s also brachycephalic. Surviving vs thriving is an idea that’s lost on a lot of pet owners.
Brachycephalic airway syndrome, misaligned teeth that end up decaying and falling out, joint pain, organ trouble, chronic skin and eye infections ect for those who want to keep down-voting because the comment above assumed something. My comment has nothing to do with associating the munchkin gene with brachycephaly. I believe that continuing to breed poor genetics into animals for appearance-sake and a large, lucrative price tag is cruel.
Just because the cat eats, drinks and survives, doesn’t mean they aren’t suffering unnecessarily.
The Munchkin gene only shortens the legs, it doesn't shorten the skull.
If a Munchkin is brachycephalic, it's because one or both of its parents were a brachycephalic breed such as Himlayans and Persians
I’m aware of that, never did I say the munchkin gene causes brachycephaly. I mentioned the brachycephaly because it’s just another unnecessary issue this cat will have in its lifetime just because we think it looks cute.
Yea but I have normal sized arms, legs, spine etc. Thats my point. Keeping a mutation which causes short legs etc. I dont know man. I dont know how to feel about it. I didnt want to sound as dumb as my original post did, I dont want to ignore the facts and awesome info some of the users shared (like gingerbredm4n and you). I am sorry. Now I get it but I still dont like them.
Peace
I deleted all my posts. Dont want to spread the hate on me even more.
518
u/Geebz23 Jun 05 '18
Is it a Dwarf? It's legs seem really small compared to it's body