Bob tailed boy - breed or mutation?

[susank521]

Bobby07-26-1302.jpg

• susank521
• Dec 9, 2013

Just wondering if anyone has an opinion on whether this fellow might have any kind of special ancestry. His tail is 1-1/2" to 2" long. Bobby showed up here about 2 years ago as an adult male, approximately 4 years old so I have no idea as to his parentage.

He had suffered a serious head/face trauma at some point in his life and sports the scars and disfigurements of a fight or two. Since his arrival here he's been neutered and had some health problems but he's doing very well right now. 

He is a rather short guy and obviously stocky. I just tried to measure his shoulder height, but he won't get up off of my husband's lap. (It's nauseating how much he ADORES my husband! Of course, my husband has never shoved pills down his throat, taken his temperature, or expelled his bladder

.) 

Any thoughts are appreciated.

 

[awaiting abyss]

Manx cats, Japanese bobtails, American bobtails, and Pixie bobs are all breeds with no tail or bobbed tails. Your cat is probably a manx or of manx descent since they are a variety of colors.

 

[Willowy]

Bobtail is a natural mutation that can occur randomly. But. . .I think your boy looks like he lost his tail in an accident . Most natural bobtails have sort of "rumpled" tails, with kinks and all that. His just looks cut off. So, especially considering his rough appearance otherwise, I think he at one point met with an unfortunate accident. He's really hit the jackpot now!

 

[awaiting abyss]

All of the natural bobtails I've ever seen look like him. My bobcat/manx/maine coon mix has a similar stub to the above cat. There is no kink or rumple.

 

[maewkaew]

 Well,  it's either due to a genetic mutation or an injury.      But it would not be a choice of breed vs mutation.    The bobtailed / tailless breeds all do have some sort of genetic mutation that causes their shortened or absent tails.  

   But I guess what you're asking is whether Bobby is a specific breed,  or whether his tail is from a mutation in random-bred cats,  separate from a  breed.    That's hard to say.  There are actually a lot of cats who have a tail mutation like that of the Manx without actually being descended from the cats of the Isle of Man.   For some reason  this mutation or some closely related mutation seems to have turned up spontaneously in separate cat populations.

Re tail mutations,  there seem to be 2 basic categories in fully domestic cats.  a dominant western gene like in the Manx ,   and a recessive  Asian one  like in the Japanese Bobtail .   It's the Manx - type ones that are sometimes associated with health problems.    & sounds like he has had some of the problems that can go with "Manx syndrome" ( which is not just related to f

So he's probably got some form of the Manx mutation.  but whether that comes from pedigreed Manx cats from the Isle of Man,  is hard to say.  The odds would be against it since there are probably a lot more cats with bobtails who are not any specific breed.    & one can't just go by the fact that Manx come in many colors,  because so do cats in general! 

 His rather cobby build is similar to a Manx.     but he actually may  be longer bodied.   I've heard them described as being like a bowling ball with legs!    but  the legs are longer in back. 

  I think about all i could say is he looks rather Manx- like,  but  may just be because he's from the same general Western race of cats,  and has the same or very similar tail mutation.   Without documentation, it's pretty hard to know if he might be partly Manx.  

  He's a good looking fellow,  and I am so glad he is now in a caring home -- and not out making more babies that might have health issues!  Thanks so much for taking this guy in. 

Besides the domestic cat tail mutations,  there's also a  possibilty that some of the bobtail cats in North America came from Bobcat matings with domestic cats.   While  I don't think there has been DNA proof of bobcat x domestic,  and Pixiebobs have been tested and no Bobcat marker found,  that may be due to the limitations of the testing.  I do think it is a possibility.

 

[susank521]

 
 Well,  it's either due to a genetic mutation or an injury.      But it would not be a choice of breed vs mutation.    The bobtailed / tailless breeds all do have some sort of genetic mutation that causes their shortened or absent tails.  

   But I guess what you're asking is whether Bobby is a specific breed,  or whether his tail is from a mutation in random-bred cats,  separate from a  breed.    That's hard to say.  There are actually a lot of cats who have a tail mutation like that of the Manx without actually being descended from the cats of the Isle of Man.   For some reason  this mutation or some closely related mutation seems to have turned up spontaneously in separate cat populations.

@Awaiting Abyss   and @Willowy  I never really considered that his bob was a result of an injury.  I had asked the vet and he didn't think so, but really, that is just a guess on his part. You probably think I'm an idiot, considering all of his other bumps and scars!

 Alls I can say in my defense is that I have another cat with a shortened tail and a hard ball on the end which the vet told me was the result of an untreated amputation. I guess I thought if the ball wasn't there it wasn't injury related.   

After reading your replies I really felt the end of his tail. His tail feels to be the same thickness it's entire length. The end is not smooth, though. It's hard to explain, but the center feels slightly concave. Not pointy at all, like a regular tail. Does your cat's feel anything like that Awaiting Abyss?

Part of your sentence regarding the Manx syndrome is missing, maewkaew. Is it incontinence you were referring to? 

 

[awaiting abyss]

Hmm... I'll have to feel his tail when I get home from work.

 

[karagraaf]

I have a bobtail- actually she has no tail or visible stub(I can somewhat feel something there though) She was abandoned but someone who knew the previous owners told me she is an American bobtail although most american bobtails have a stubby tail at least. also the stub tail in an American bobtail is a dominate gene. She was pregnant when I got her and 2 out of the 6 kittens are bobtails too- the have cute little stubs!

 

[maewkaew]

 
@Awaiting Abyss   and @Willowy  I never really considered that his bob was a result of an injury.  I had asked the vet and he didn't think so, but really, that is just a guess on his part. You probably think I'm an idiot, considering all of his other bumps and scars!

 Alls I can say in my defense is that I have another cat with a shortened tail and a hard ball on the end which the vet told me was the result of an untreated amputation. I guess I thought if the ball wasn't there it wasn't injury related.   

After reading your replies I really felt the end of his tail. His tail feels to be the same thickness it's entire length. The end is not smooth, though. It's hard to explain, but the center feels slightly concave. Not pointy at all, like a regular tail. Does your cat's feel anything like that Awaiting Abyss?

Part of your sentence regarding the Manx syndrome is missing, maewkaew. Is it incontinence you were referring to? 

Yes sorry that got cut off.   I was going to say that "Manx syndrome" is related to the gene,  but not only to the breed. It's just named after the breed ,  but could happen in unrelated cats who have the same sort of absence of tail.   and yes incontinence is part of the potential problems they can have.)

The American Bobtail  is a breed that came from random-bred cats in North America who had this dominant tail mutation  that it at least similar to the one in the Manx.  They do usually have at least a stub.  but I guess it's not surprising they could have a "rumpy" also like the Manx.    

I think it's the Asian cat tail mutations that definitely usually have some curl to the tail.  

 

[awaiting abyss]

My Soren's tail feels similar to how you described with the concave feeling.

 

[susank521]

I have a bobtail- actually she has no tail or visible stub(I can somewhat feel something there though) She was abandoned but someone who knew the previous owners told me she is an American bobtail although most american bobtails have a stubby tail at least. also the stub tail in an American bobtail is a dominate gene. She was pregnant when I got her and 2 out of the 6 kittens are bobtails too- the have cute little stubs!

I've seen some of your posts about your pretty girl & her kittens. I'll have to look for some of your recent pictures. BTW - Cheers for you for taking her in!

@Awaiting Abyss  how long is Soren's tail? Bobby, with his short little nub, will sometimes accidentially roll backwards/sideways when he's trying to groom his back. Some of that could be a result of his weight though, not from his lack of a tail. His little nub does wiggle and wave alot, too, especially when he's being petted.

Just out of curiosity maewkaew, would you think that Karagraaf's litter, 2 out of 6, would be a normal ratio if one parent has the gene?

 

[awaiting abyss]

That sounds like the rolling would be cute to watch.

Soren's tail is almost 2 inches. Between 1 and 1/2 inches and 2.

 

[karagraaf]

Yeah I really have no idea if she truly is an American bobtail cat, I was expecting her to have more kittens with bob tails and one of the kitten's bobtails looks almost curled. So who really knows when you rescue a cat!

 

[maewkaew]

@Awaiting Abyss.
Just out of curiosity maewkaew, would you think that Karagraaf's litter, 2 out of 6, would be a normal ratio if one parent has the gene?

(With a reasonable assumption  that this is a dominant mutation   with the mother carrying one copy,   if we then also assume the father does not have the mutation at all)   the theoretical percent  would be 50%.   so if you apply that to this litter,  it means it turned out 1 kitten lower than 50% which would have been 3 out of 6 .    But really,  that 50%  refers to the chance of each individual kitten inheriting the mutation,  so of course one can't make an exact prediction of how many in the litter will have it.   It's like flipping a coin .  Each time you flip it,   there's a theoretical 50% chance you'll get Tails ( I almost typed "Heads" , then I thought that for this discussion I should make it "Tails"

).  But in flipping it 6 times,  you won't necessarily get tails exactly 3 times. 

You can make a simple little Mendelian inheritance chart. 

  T =  the mutation for short tail.  t = normal tail.     The mom's contribution is shown on the left side.  the dad's on the top.   Mom has one copy of T and one copy of t.  Dad has 2 copies of t.       So here is how they combine:

	t	t
T	T/t	T/t
t	t/t	t/t

You can see that 2 out of the 4 possibilities have a  "T",  representing the tail mutation for short or absent tail.   The T is dominant over t.  so anytime a kitten gets even one T,  they get the trait.

(This is actually oversimplifying things. 1.   there are some genetic traits where they might have the gene but NOT develop the trait.  but I think this tail thing has very high penetrance -- meaning almost all who have the gene will have some form of the trait.    2.  The tail mutation is  variable in expression,  meaning some kittens may get shorter tails than others.   )

 

[maewkaew]

  re the curls ,  I guess I am thinking of the Japanese Bobtail & how they have the pom pom tail look due to the way their little short tail is kind of curled.

 but I shouldn't say the  Western varieties don't have some curl.

There's also another mutation for a "ringtail".  It's not an officially recognized breed.  but it's a known mutation that has turned up in some cats in North America at least ( maybe other places but I know of the North American ones) .

 And HOW on earth could I have forgotten to mention the tail mutation in my own breed?   I guess because it's not strictly a bobtail thing,  though it sometimes does result in a shortened, thickened tail ,  often it is just a little bend toward the end of a long tail.   I'm talking about the tail kink that is common in cats in Southeast Asia, and which used to be very common in Siamese,  but breeders long ago decided to make it a disqualification for show,  and it has been to a great extent bred out,  though it can still pop up occasionally even in lines that have been in the West for over 100 years.   And now we're getting it back  due to importing Siamese (Wichienmaat)  cats from Thailand to expand genetic diversity .  

This is not the same as the Japanese Bobtail   and not the same as the Manx.   It's a dominant gene with variable expression,  but unlike the Manx gene, there's no associated health risk;  it's purely cosmetic.

 

[susank521]

 
(With a reasonable assumption  that this is a dominant mutation   with the mother carrying one copy,   if we then also assume the father does not have the mutation at all)   the theoretical percent  would be 50%.   so if you apply that to this litter,  it means it turned out 1 kitten lower than 50% which would have been 3 out of 6 .    But really,  that 50%  refers to the chance of each individual kitten inheriting the mutation,  so of course one can't make an exact prediction of how many in the litter will have it.   It's like flipping a coin .  Each time you flip it,   there's a theoretical 50% chance you'll get Tails ( I almost typed "Heads" , then I thought that for this discussion I should make it "Tails"

).  But in flipping it 6 times,  you won't necessarily get tails exactly 3 times. 

You can make a simple little Mendelian inheritance chart. 

  T =  the mutation for short tail.  t = normal tail.     The mom's contribution is shown on the left side.  the dad's on the top.   Mom has one copy of T and one copy of t.  Dad has 2 copies of t.       So here is how they combine:

	t	t
T	T/t	T/t
t	t/t	t/t

You can see that 2 out of the 4 possibilities have a  "T",  representing the tail mutation for short or absent tail.   The T is dominant over t.  so anytime a kitten gets even one T,  they get the trait.

(This is actually oversimplifying things. 1.   there are some genetic traits where they might have the gene but NOT develop the trait.  but I think this tail thing has very high penetrance -- meaning almost all who have the gene will have some form of the trait.    2.  The tail mutation is  variable in expression,  meaning some kittens may get shorter tails than others.   )

"Tails" it is! 

 Thank you for the explanation (and for dumbing it down so I could half way understand it). Biology was never my strong suit with all of it's variables and gray areas, I get lost in the maze looking for a mathematical absolute. 

 I do understand now that Bobby's 2" tail is a result of the same gene as my Sophie's  7" tail (logistics make it very doubtful that there is any genetic relationship between the two cats). Sophie came from a rescue situation where there were 28 cats. When I came upon them she was the only one with a noticeably shortened tail.

 

[susank521]

That sounds like the rolling would be cute to watch.

Soren's tail is almost 2 inches. Between 1 and 1/2 inches and 2.

It is cute. After he rolls over he'll jump up and look around to see if anybody saw him do it. Poor guy really looks embarrassed.