Tail Kinks Becoming More Common

[artes]

Actually, my point on Twistie was that no one adopted him for 8 months because of his tail. My point is that people put too much emphasis on perfection, and not enough emphasis on life.

Can you imagine if humans decided that blue eyes were inferior because they're sensitive to the sun, so they decided to start putting down all blue eyed babies for the "good" of genetics? And before you pull out an "apples to oranges" argument, I happen to view all life as the same. Actually, I like animals slightly more, to be honest.

 

[geckogirl3]

i have a question, if a gecko was born with a kink in their tail, and got in a fight and lost the kinked part, would the kink be there when it grew back?

Hate to be inpatient, but does anyone know the answer???

 

[sunshinegeckos]

i have a question, if a gecko was born with a kink in their tail, and got in a fight and lost the kinked part, would the kink be there when it grew back?

I think it would depend on the reason for the kink. If it was genetic and it was something with the spine then probably but if it was an accident that caused it probably not. That would just be my guess

 

[geckogirl3]

ok thanks

 

[M_surinamensis]

I'm so lazy. So very, very lazy.

COPYPASTA! (with some minor contextual edits)

Looking at a single gecko, the exact cause of such a condition is usually going to be an unknown. Setting aside conditions resulting from infections and injuries the three most common reasons would be developmental deformities, nutritional deficiencies/imbalances (which may have resulted in a developmental deformity) and genetic deformities. Unfortunately, there's not much most individuals can do to determine which of these is the case for their specific pet.

Developmental deformities happen when something goes wrong while the animal is growing, in or out of the egg. Temperatures outside the ideal incubation range are one of the more obvious reasons, but there are numerous potentials. The moisture content, contact with contaminants that are capable of penetrating the permeability of the eggshell, the position of the developing animal, the nutrient content of the egg yolk and so on. I mention the nutrient content of the yolk specifically because development and health is highly dependent on vitamin levels and under or over supplemented females can produce yolks with variable amounts of vital, but trace, nutrients.

Nutritional imbalances during growth post-hatching can cause problems as well, underfed, overfed, under supplemented, over supplemented, the environmental conditions can have significant effects; every cell in the animal's body has a growth rate that is dependent on all these external factors and on the intake and regulation of necessary nutrients. If they're a bit off, things can grow... wrong. Too fast, too slow, too much, not enough, the wrong shape, the wrong size.

Genetics mandate or contain the potential for everything an animal inherently is, before environment gets in there to start mucking it up. It is possible that any displayed trait which is not a product of a known and verifiable external cause could be genetic. The method of transmission is not always simple and the strength of expression is not always an absolute, but until such a time as genetic mapping becomes cheap and easy, there's no way for most people to determine such things without extensive test breeding. Given a trait that has, or increases the likelihood of, quality of life issues, test breeding is not an ethical choice, as it creates additional offspring with the same problems or spreads around the gene (if it is genetic) responsible for the problems without necessarily expressing them.

Since there's no reasonable way to determine the cause of a visible condition that an animal was born with or developed as it grew when there was no specific instance of acute injury, all such instances should be treated as potentially genetic. Deformities that result from developmental problems are isolated to the specific affected animal, genetic problems are potentially inheritable and can affect more than one animal if handled improperly. Can't tell which is which, so they should all be regarded as the more severe and dangerous of the two.

Which leads to the subject of genetic management.

When we place animals in captivity, we usually retard or remove the process of natural selection. We dramatically change the threshold for survival and we dramatically change the method of mate selection. Many of things that are priorities in wild populations, the ability to avoid predators, the ability to find food, a strong immune system, efficient digestion or aggressive breeding tendencies are things that simply stop mattering that much in captivity. We breed for color and pattern and docile behaviors- things that mean success for a species that is going to live in a box with readily available food, no predators and regular vet visits. Our choices about which males and which females get bred have replaced the natural process of surviving to adulthood and being healthy enough to mate. We are responsible for every single trait that gets propagated in our captive animals, good or bad.

If we manage them properly, there's a lot of potential for healthy, perfect lizards, in whatever weird colors you like. If we mismanage or fail to manage our captive populations, there's a tremendous potential for unhealthy, twisted, deformed, suffering and sickness. A lot of these initial presentations seem like cases which are on the fence... a gecko with slightly bulgy eyes or a slightly curly tail or slightly stubby toes doesn't seem like such a big deal. It still gets around, eats on its own, does all the usual gecko things. Expression of a trait is not always linear though, slightly kinked might have no obvious negative effects, but two generations down the line, they might be excessively kinked further up the spine or in other joints, twisted, crippled and in constant pain.

So when you get a condition like this, it needs to be treated as if it were genetic, it should never be propagated, the animal always has the potential to breed unless it is sterilized or culled. Sterilization is difficult, impractical to a degree that borders on impossible when looking at a lizard that probably weighs under 100 grams. Culling is an absolute however, the humane euthanasia of an animal in order to remove the risk of it ever passing along its genetic material.

You may never intend to breed the animal, you might never do it while it is in your care and ownership. Unfortunately there are circumstances which can remove the animal from your ownership that are beyond your control. If you die or are injured to a degree that prevents you from keeping them, if you lose your job or your house and are forced to give them up, if they are stolen or escape; there are ways for you to lose control over the animal that are unpreventable. Leopard geckos can live for twenty years, two decades... that's a long time with a lot of potential for things to go wrong. What an owner does have control of is the animal right now.

Ultimately it comes down to risk management. The potential for negative consequences is present, those negative consequences are severe (take a look at leucistic texas rat snake eyes or kahl line albino boa constrictors) and can quickly get out of hand, affecting large numbers of animals. In order to manage the risk, to eliminate it completely, culling is the only real option. Fast, clean and as painless as possible, for the future of the captive population. It's a responsibility and a moral obligation that we accept when we choose to own the animals. No matter how many other people may not fulfill it or want to hide from it.

And this one...

You will notice a distinct and almost complete divide between the people who are proponents of culling and those who are not.

The experienced, educated and professional members who have responded favor culling.

The inexperienced, under-educated and neophyte hobbyist members do not.

Those who have a vested interest in maintaining healthy captive populations, who understand the potential causes and who understand the potential impact such visible deformities can have all line up on one side.

If you do not align yourself with that viewpoint, then you have no business propagating animals. When you choose to breed you have a responsibility, not just to your own pets but to the entire species; when you choose not to cull you are failing to live up to that responsibility. It is not fun, it is not easy- but it is right. Do the right thing and terminally cull this deformed lizard. If you can't or won't, then stop breeding, immediately and never do so again until such a time as you can fulfill all of the obligations that come with it.

And another...

It is Wikipedia, but at the time I am posting the links, they're accurate enough.

http://en.wikipedia.org/wiki/Dominance_relationship

Not every trait is a simple recessive.

http://en.wikipedia.org/wiki/Non-Mendelian_inheritance

Not every trait necessarily follows Mendelian laws for the method of inheritance.

Since tail kinks have not been mapped, and since there are multiple potential causes for tail kinks which may not be genetically identical (think tremper and las vegas albinism) the method you outlined above would not do anything except potentially spread a recessive genetic kink into the general population as you unloaded offspring who were not visibly displaying the trait.

If you want to keep a few thousand leopard geckos across fifteen odd generations though, you could probably get a pretty good idea of the genetics involved if you were bright enough to do the right test pairings. Pretty big investment in time, effort and money just to determine that you have produced a sub-line that doesn't carry the genetics for a kinked tail though, considering the ready availability of stock that wouldn't require similar lengths. It is massively easier to just buy a different gecko for a breeding project than it is to begin the process of proving a negative using test breedings.

Although if you have a few hundred thousand dollars laying around, I'll happily make a couple phone calls to people with the existing lab equipment required to really get into leopard gecko gene mapping and knock you up a blood test for any single trait you want.

And...

A tail kink is a symptom. It indicates that something has happened which has caused the tail to grow in a way which is not normal.

There are multiple reasons why a tail can be kinked, multiple causes that lead to the same visible symptom.

They can result from injuries, a good nip by another gecko if they were being housed communally that caused a break between the bones of the tail that healed crooked. Or partial tail autotomy, where the tissue on one side of the tail separates while the other remains intact can cause a little regrowth that pushes the entire thing into a crooked direction.

They can result from incubation issues. If the animal develops folded inside the egg in an odd direction where there is not enough space for normal growth. In some cases os temperature fluxuations, it can alter the rate of cell division for a period of time, changing the development of the tissue which is growing during the period of changed temperatures- although for something like a tail kink, a temperature fluxuation would also likely result in limb abnormalities.

It can be the result of a genetic condition- however exactly what that genetic condition is can be difficult to determine. It might be a genetic change in the soft tissues, it might be a genetic change that makes the animal prone to abnormal calcium deposits, it might be a change to the connective tissue or lubricating fluids along the spinal column, it might be a genetic condition that changes the ability of the animal to metabolize calcium and the tail kink is a result of the regulation of available nutrients, it might be a change to the size or number of vertebra...

There are dozens, hundreds of underlying causes for a single visual symptom like a tail kink.

Some of them could never manifest in any other way or cannot be passed down through the genetics.

Some of them are genetic and might have a different strength of expression. One kink between two of the bones way down the tail is a pretty small problem. One kink between every vertebra all the way up the spine is a serious problem. Calcium deposits at every joint is a serious problem. An inability to properly metabolize nutrients required for healthy bone growth is a serious problem.

It is perfectly fine to breed an animal if it has a kinked tail as a known result of an injury- it had a perfectly fine tail, it got bit or dropped or some dope pinned it with a little ceramic cave and then it was broken and bloody and healed crooked.

If it is an unknown, hatched out that way or developed for no readily apparent and easily verified reason, then it is not okay to breed it because it might be genetic.

The risk is tremendous. The gain is nonexistent. Healthy, normal leopard geckos are all over the place for low prices. There is no reason to breed an animal with deformities. Or any other health issues. Only an unscrupulous scumbag or someone who is profoundly ignorant would propagate animals using stock that should have been rubberstamped as defective.

And this one...

I wouldn't assume anything.

Incubation/development snafus are the most likely, based on probability and with unknown lineage.

However, especially in leopard geckos where there have been numerous cases of genetic kinking, a genetic cause is on the table fairly high in the probabilities.

Look at it this way... what kind of chance, as a percentage or a ratio, would it need to be for you to draw a line between acceptable and unacceptable risk? Keep in mind that assuming it is an incubation problem would allow someone to treat it like every other gecko when it comes to breeding projects. If there was a fifty fifty chance, not many people would take it, but what about a twenty five percent chance? Ten? Five? One? Just how low do the odds have to be before someone risks screwing with an entire captive population for decades to come? I think it needs to be treated like an absolute. Any possibility, no matter how minor or remote, of a genetic cause and it needs to be treated as if it were genetic. The potential negative consequences just outweigh any arguments to the contrary.

Oh, and here's this...

Not necessarily.

The more rare or desirable traits an animal possesses, the more likely it, and its offspring, are to end up being prolific.

Kahl line albino boas are a pretty good example of how such a problem can get out of hand if people choose to ignore genetic management. The line has a high frequency of eye deformities, misshapen eyes and missing eyes are comparatively common relative to the rate of similar problems in the general population of the species. The eye deformities cropped up pretty early on- exactly how early is unknown, since the people who initially produced the morph and those who heavily invested in it prior to sales to the general public refuse to share what they know. By the time they were listed on online classified ads and showing up at reptile shows- still expensive, but available- it was widely known that the problem existed and that it was genetic.

Some people bred them anyway, because they didn't care.

Some people bred the siblings of deformed animals, because they didn't care. Or because the person they bought it from had destroyed the deformed individuals and then lied about the problem appearing in the clutch.

Lots of people were outbreeding, trying to create hets to expand their future projects. Mixing up the eye deformity genes with the general population.

Eye issues are now more common in boa constrictors, even those which aren't involved directly in albino projects, than they were before Kahl loosed the cycloptic genes on the open market. It is still not a common problem outside of albino breeding lines, but it is more of a problem than it was before by an exponential factor.

A similar situation happened with texas rat snakes and the leucistic morph decades ago- and these days in captive populations, the "bug eye" trait is all too common among animals which both are and are not leucistic. Two random normals bred together can produce bug eyed babies- because they have been contaminated by indiscriminate breeding and lax genetic management.

So your gecko missing a toe example... if the gecko has a nice color or an unusual pattern, it would be bred by someone unscrupulous and it would end up out there.

Quite frankly, there are people who, as I said, just do not care about the damage they are doing tomorrow as long as they can make a buck today. And a bunch more people who just don't understand why it is so important. That is why people who have been proponents of aggressive culling on this board recently see it as being such a big deal; they want everyone who is inclined to do the right thing to be fully informed and to use that information to make the right- though difficult- decision if they ever find themselves in a situation where euthanasia is the indicated course.

The bad guys are already going to be doing bad things, the people who just don't know any better can be stopped though, they can be educated and they can be set in a better direction. If everyone who had good intentions had the right information to practice appropriate culling procedures, they would constantly strengthen the captive stock and minimize the damage done by the unscrupulous types. Furthermore, it would reduce the market that the scumbags prey upon- jerking the heartstrings for a quick sale of a substandard animal.

Getting back to the missing toe example as well... just because a trait is expressed in one individual as a minor defect, that does not mean that there is not greater potential for worse defects inherent in the negative mutation. That one missing toe from the stock animal might end up being no toes a few generations later- or worse, depending on exactly what a defective gene is doing to cause the visible result.

And this...

I have a will. Written by a lawyer, enforced by property law, all my assets and possessions including the animals all specifically listed in it* and going to people who share my position when it comes to... basically everything when it comes to keeping animals.

I don't buy or sell too many animals. Not in about a decade anyway. It is not something I do professionally, at least not in a production capacity and I like what I currently have and have used much of my available space to obtain exactly what I wanted. I breed very selectively when I want to produce something for a specific individual who likes the same species and on rarely when some friends who do run businesses request it of me- that and feeder colonies that never quite seem to be in perfect balance, although I am not too far off my target.

I still cull. Every single time it is appropriate to do so. I never want to cull, I love animals (although... perhaps not quite the same way other people do) and never want to be responsible for their death. There are practical concerns though, backed by a code of ethics that makes culling a mandatory action under some conditions. By owning animals, by choosing to breed them sometimes, I am shouldering a responsibility to make the absolute best decisions I possibly can for the good of my own animals and for the good of the entire captive population.

I cannot guarantee beyond all doubt that my animals will always be my animals. The life span of the species I keep can vary- the reptiles tend to range someplace between about ten and thirty five years though. Some of the amphibians are in the same range (some are a bit shorter), some of the fish can actually exceed that. I wouldn't even contemplate voluntarily owning chelonians or psittacines based on their life spans.

My ownership could change at any time. Any time. If I get hurt or sick or dead, there goes my control. If half my house burns down and I move to a new town, that new place might have regulations that prevent me from keeping my animals. I could go broke and have no choice but to rehome them because I can no longer afford them. I might get married** and my hypothetical wife might be allergic or phobic or just want to turn one of my animal rooms into something else. I might find a new interest and need to make room for myself. Someone might burglarize me and steal some of the animals.

Anything could happen. Absolutely anything. Most of it probably won't and I take as many precautions and plan for as many contingencies as I can, but I can't guarantee that I'll own all those animals for the remainder of their life.

So I have to cull. It is the only way to be sure.

And on.

And on.

And on.

And ON.

And ON.

I've personally written responses in over two dozen threads about deformities and culling and selective breeding and genetic management and the responsibilities we have to the quality of the captive population in the last six months. I've ignored at least as many threads on similar topics, because someone else already said what I was going to say. There are dozens and dozens more threads predating those six months, including a couple of them with graphic photographs of the potential outcome of breeding animals with kinked or curled tails. This is something about which there is only the most minimal disagreement among experienced and knowledgeable herpetologists and herpetoculturalists, and all the disagreement is in the details of the disposition. Something that has been written about extensively by some of the best and brightest people to ever keep reptiles in captivity.

But what the hell, Artes thinks it's cute and wants to draw parallels to blue eyed human beings. That clearly trumps any argument to the contrary.

 

[M_surinamensis]

I think it would depend on the reason for the kink. If it was genetic and it was something with the spine then probably but if it was an accident that caused it probably not. That would just be my guess

If it was genetic, it would also depend on exactly how that genetic trait was manifesting. Not every kink is the same... outside of the genetic/congenital/injury distinctions there are also different ways that the same visible symptom can be caused. Size, shape and positioning of the skeletal structure, of the connective tissue between the bones, of the muscle tissue surrounding that, of the formation of the capillaries that bring blood to buildups of fat cells, to the shape and placement of the rings which allow for caudal autotomy... they can be a genetic predisposition for the shape of a bone, for the way the animal's body handles nutrients, or the way it produces growth hormones... scores of possibilities.

Different causes can manifest differently when subjected to injury and regrowth (or surgical removal). Some will grow back the way they were, some might appear more normal but re-develop the problem over time, some might not ever display the issue again (remember, significant tail loss often regrows in a stumpier, thicker shape, where abnormalities at the core of the tail may not visually manifest as easily) but are still genetic carriers, transmitting the genetic condition to their offspring. Since they aren't always as easy to predict as simple mendelian traits, a single generation of seemingly problem free offspring cannot be used as confirmation of a negative when it comes to genetic carriers.

Short answer... too complex to predict reliably.

 

[enigmachine]

Again I am very new here.

Based upon some of this reading.
Could you not breed out that trait, by going back to Wild Leos?
Meaning take the inbred traits of whatever is going on and cross them back to the wild leos. Theoretically this would boost immunity right, and some other favorable things.

Could these Tail Kinks be the result of inbreeding and crossed inbreeding, at least in the more recent times?

Again I have a lot to learn, but it seems to make sense to try and cross back to a wild Leo in order to minimize certain problems?

Are wild Leos not prized at all? (there is a ton of information here so if some of this has been mentioned before, I apologize).

Suri- Too bad people didn't do that with dogs, some breeds should not exist. Too predisposed to genetic problems. I can appreciate your ethical understanding.

On another note: You mention Eugenics only as a comment in regards to someone else. What do you think happened in this country with slaves. Unfortunately humans were forced bred for traits. America is the original land of Eugenics, as shameful as it is to say.

 

[M_surinamensis]

You mention Eugenics

No. I didn't.

I double checked the quotes to be certain it hadn't slipped in there as I was copying and pasting text from other threads. I do not, at any point, mention eugenics.

Eugenics carries with it the context of application to human beings, with all the associated ethical considerations, moral gray areas and debate that such topics carry. Genetic management of an animal population may employ methods which appear similar on the surface (selective pairings, the destruction of negative traits) but cannot be said to be genuinely analogous, because human beings are not identical to other animals.

The closest that I came was the condemnation of Artes' posts, where she tried to draw parallels between culling a reptile that was born with a deformity and culling a cat which was injured or culling blue eyed children. It was a rejection of the concept, not an endorsement.

 

[bohannbj]

As far the the tail regen goes, the kink would not come back. I believe a regrown tail-bone is a straight solid bone instead of a segmented one. This is why they can't sway it back and forth. It would be like growing your hand back but not being able to move your fingers. I wonder if they feel the same as people who get their brand new car stolen, or eaten in their case, and the insurance company sends them a 3 year old replacement.

 

[lillith]

As far the the tail regen goes, the kink would not come back. I believe a regrown tail-bone is a straight solid bone instead of a segmented one. This is why they can't sway it back and forth. It would be like growing your hand back but not being able to move your fingers. I wonder if they feel the same as people who get their brand new car stolen, or eaten in their case, and the insurance company sends them a 3 year old replacement.

Actually, regrown tail is all cartilage and fat. And skin. No bone.
Okay okay, I suppose there are blood vessels and the like, too. But no bone.

p.s. here's the "curly-tailed" thread for those that might be curious:
http://geckoforums.net/showthread.php?t=43198&highlight=curly

 

[contracteryin]

Oye vay. I'm sure glad I read this, I learned a lot and I'm reading the curly tail thread now. Whenever I get into breeding *shouldnt be anytime soon* I'll or sure be looking for any problems in babies and stuff, and already I'd only choose healthy individuals. Personally I'm not even a fan of Engimas cause of the issues they have. Of course, I dont mind if people like them.

 

[enigmachine]

I just know, that if someone is breeding for a specific purpose, eventually you will cross lines that should not be recrossed, without some repercussions.
A theory would make sense to use wild animals. Wild Leos to rethread some life back into the genetically bred stock that seems to be out there. Might yield something new.

I've been looking and it seems you can buy a leopard gecko from anywhere and from nearly anyone. Not to say that all breeders are created equal, but it does seem that a lot of people consider themselves professionals in the field.

All right, I got on a tirade about eugenics, my bad. But it did appear that it was being mentioned subversively to me. Then again, I read into things sometimes.

I know little, but am constantly reading... So again, why wouldn't introducing wild leos into the mix create some balance back into a genetic pool that may be slowly starting to show it's flaws... Has this even been considered. What if these genes were there 40 generations ago, but we didn't know, and obviously now those genes are more dominant, or key recessive, regardless, now these things are more apparent. Possibility?

 

[Chosen010]

My question would be regarding the parents and culling leos that are juvies through adults....

If you are breeding and one member of your clutch displays a tail kink, shouldn't you stop breeding both of the parents because while they may not display the visible trait, at least one of them is highly likely to be carrying a tail kink related gene???

Furthermore, to build on the theory of culling animals that display physical abnormalities, what happens when this is displayed as the animal ages to a juvenile or sub-adult? What is one supposed to do? Euthanize?

 

[UnicornSpirit]

unlike many mammals, leos can not be spayed/neutered if there is a defect (to keep it from breeding and passing on the trait).

Actually, you CAN get your reptile neutered or spayed. It just costs a pretty penny. So, I highly doubt many people have it done.

A friend of mine had to bring one of her leos' in for egg binding and while the vet was treating that he spayed her in request of the owner (for fear it would happen again and she would lose her beloved gecko).

 

[M_surinamensis]

Actually, you CAN get your reptile neutered or spayed. It just costs a pretty penny.

While you are right and it is technically possible, there's more to the reason it is extremely rare than just the cost. There are very few vets that are both qualified and willing to do it. Reptile anesthesiology and aftercare are inherently far riskier. The smaller the animal, the higher the level of difficulty and risk associated with such procedures.

The few vets who are capable of performing such an operation usually won't do so unless the animal is afflicted with a medical condition which would otherwise be certain death. The mortality rate as a consequence of the surgery then becomes an acceptable risk, since there is no alternative. How willing they are to listen to a debate along the lines of "sterilize or euthanize" is personal and uncertain at best.

It's really not a feasible method of casually ensuring a pet will not breed, at least at this time for the species in question.

 

[Kristi23]

My question would be regarding the parents and culling leos that are juvies through adults....

If you are breeding and one member of your clutch displays a tail kink, shouldn't you stop breeding both of the parents because while they may not display the visible trait, at least one of them is highly likely to be carrying a tail kink related gene???

Furthermore, to build on the theory of culling animals that display physical abnormalities, what happens when this is displayed as the animal ages to a juvenile or sub-adult? What is one supposed to do? Euthanize?

You don't know that the kink was caused by the parents genes. I've bred the same pairing for three seasons. This season was the first time I had two very small tail kinks from them, but I knew our air conditioning broke during the hottest week of the year. My incubator temp went up about 4-5 degrees during this time. I wouldn't have a problem breeding them again. If I had tail kink issues the following season with their babies, then I would stop. If I ever noticed a trend, I would stop breeding them. Since the male is with many females with no issues, then I would assume it was the female. It's really up to you as a breeder. Just be ready to cull the babies with deformities so they're not bred.