Reptile & Amphibian Forums

I have a female gecko that I would estimate is approximately 2.5 - 3.0 years old. She was purchased at the NARBC in Chicago in 2004. The breeder told me that her tail abnormality was genetic, and not the result of her tail being lost at a previous time, and I'm inclined to believe her as the tail has not lost the 'ringed' appearance that original tails have. The abnormality has shortened the tail - a good parallel to draw would be if a normal tail is like an open accordian, her tail is like a closed accordian. In 2005 I bred her to my male for the first time and she produced 3 eggs, all laid singly (she did not lay any pairs). 2 of the eggs hatched, 1 of the geckos survived, and I believe that she was probably a tad small for the breeding - she was between 40 and 45 grams. (I had read somewhere that you can breed as early as 35 grams, and thought that it would be okay.) I decided not to breed her this year, mainly to try and fatten her up and get her healthy and ready for next year, hopefully around 60 grams, and ready to go. I feed her 4-5 days per week, approximately 7-10 adult crickets, yet she does not seem to be able to get much past 50 grams. She has large fat deposits behind her forearms, and she is nice and plump looking in the belly, and even in the shortened tail. Obviously the shortened tail will take off a few grams from what a gecko with a normal tail would weigh, but is it possible that the shortened tail would render her a poor breeder? If anyone out there has seen a tail like this on a gecko, please let me know - I'll try and get a good picture of her in the next day or so and post it.

Sorry for the length, just wanted to be explicit.

Thanks,
Brandon

Shouldn't be a problem if the tail was too small you should see the girth reduce drastically. At that age she should be bigger but regaurdless she is big enough. I assume she had 3 seperate clutches? and not that she laid three eggs a day or two apart from one another. Three consecutive clutches of one egg each would suggest poor breeding on her end maybe only one side of her reproductive sys. works for whatever reason. next time check to see how they are developing and where before she lays. As for survival rate that could be anthing. examine your own husbandry on her end end the eggs and see if you can find anything that you are doing to be inconsistant with what others do. I realize some of this you probably know but im hitting all possibilities here.

and yes, it was 3 seperate clutches of one egg each. I'm hoping that it was just a tad early for her and not that only one side of her reproductive system works... only one way to find out I suppose... I'm going to try and get her to a solid 57-60 grams, and then toss the man in with her. The only problem I've ever had with husbandry (my own fault) would be retained shed on fingers/toes - (I am quick to help them with a qtip and some warm water, it usually comes right off) - the problem has only occurred with the baby, and the adults have always appeared happy, healthy, plump and good lookin, so I think I've got everything else mostly right. I'm gonna do my best to get that pic together - this tail is quite funny looking - (my girlfriend thought it was cute, and so of course, it was purchased.)

Thanks again,
Brandon

Why are you trying to breed a leo with genetic faults anyway?

I am not 'trying to breed a leo with a genetic fault' - more accurately I happen to have bred a leo with what could be a genetic ABNORMALITY - big difference from a genetic fault. She has been bred only once, 2 summers ago, purely for the enjoyment of doing so, watching the babies hatch, etc., and now I am wondering if this tail could have an effect on her breeding success. I haven't bred her since, and in all actuality probably won't, but I still wonder if anyone has seen this or knows about it. There is a local swap where I know I can get rid of babies if need be. (For the record, the baby I still have has a normal tail.)
And perhaps I was inaccurate in my original description - I cannot for sure say that the breeder told me the tail was a genetic abnormality, but only that the gecko had always had the tail like that, and that it was not due to tail loss.

My point is that that is a know genetic fault that is caused by years of inbreeding. Now you have added to the amount of animals with weak genes in captive populations instead of doing the responsible thing and culling it from a breeding program.

Just because an animal has an abnormality doesn't mean its genetic, it could be a birth defect from myomere division among other things. If it is genetic that doesn't mean is inheritable. If it is inheritable a short tail or other "abnormality" doesn't mean it's a problem for the health of the individual. As for "weak" genes that is an entire lecture for a genetics class, not to mention i didn't read that it was being bred to a sibling. Also if this is a genetic abnormality it probably doesn't have anything to do with inbreeding. Inbreeding isn't like a hollywood horror film where sibling mountain folks have sex and produce four arm gaint murderers.

Inbreeding or line breeding results in a loss of heterogeneity in the alleles of a population, in this case the captive breeding population. Yes, it will not always lead to birth defects as the genes that are responsible for the defect may not have been present in the founding population. If the founding gene pool does include faulty genes, line breeding will increase the likely hood that these traits will be expressed. Responsible breeders who line breed their animals are always looking for the expression of traits which are considered to be detrimental to the captive gene pool. If these traits pop up then the deformed animals are culled along with the parents. However not everyone who breeds animals is willing to accept this responsibility. That is why there is a problem with bug-eyed Texas ratsnakes and albino boa constrictors that are missing eyes.

Ron Tremper has line breed his animals for many generations. However, he at one time noticed that animals were being produced that had abnormal body proportions such as a shortened tail length. He then imported new animals to outbreed his line and in turn strength his captive gene pool. That is responsible. Buying animals with genetic abnormalities, possibly because they were cheaper, and using them to start a breeding project is irresponsible.

I understand all that. After attacking the poster for trying to breed this leo you said:

My point is that that is a know genetic fault that is caused by years of inbreeding. Now you have added to the amount of animals with weak genes in captive populations instead of doing the responsible thing and culling it from a breeding program.

Basically i said you don't really know that it is genetic just because it was born that way and even if it is genetic it may not be inheritable. I don't recall any post saying this was a line bred animal, it could be wild type for all I know. Also who is to say that the loss of a ringed tail replaced by a smooth is "weak genes". By culling genetic abnormalities you are also decreasing the overall allele diversity for the captive population. Who is to say that this is not a mutation. (i still want to see a pic of the tail) We also do not know if the female is being bred to a wild caught male or a 20th generation captive bred. There are quite a few assumptions here to question someones breeding morality. Line breeding is artificial natural selection anyway so if Tremper wants to line breed orange geckos culling only noticeable defects not metabolic, neurological, and other non visual problems (that may be carried geneticaly but not expressed) instead of brown wild caughts and others want to produce albinos (an actual detrimental gene) consistently within a line and kingofrain wants to breed smooth tailed leos (not proven genetic trait much less proven detrimental)then who cares. I believe KoR bought the animal because of this novelty not because it was cheap. In short this could be a tail regrown with lies to sell it and other than that we know nothing about the breeding program assigned to it only its success rate of production which may be a husbandry problem or something else not inheritable so don't go jumping on people over huge assumptions.

>>Basically i said you don't really know that it is genetic just because it was born that way and even if it is genetic it may not be inheritable

But it might be, and that is reason enough. Also, the breeder told him it was genetic, so whether it is or not, he had to start with the assumption that it is.

>>Also who is to say that the loss of a ringed tail replaced by a smooth is "weak genes"

He said the tail still has the ringed appearance. It is only shortened in what he described as an accordion type way.

>>By culling genetic abnormalities you are also decreasing the overall allele diversity for the captive population.

Maybe, but it is worth it to get rid of any possible unwanted genes.

>>Who is to say that this is not a mutation

Well if it genetic, then it is a mutation.

>>We also do not know if the female is being bred to a wild caught male or a 20th generation captive bred.

Wild caught imports are extremely rare, the countries in which they are found are not known for exporting thousands of animals from their natural populations.

It is not all the original posters fault. The person who started the problem was the breeder who sold him the animal. It should not have lived any longer than it took him to see it and euthanise it. However money is a funny thing that makes people do immoral things. The original poster was ripped off IMHO and I feel sorry for him. But he should also know that if a buyer finds out that he was sold an animal from a deformed parent it would ruin his reputation as a future breeder.

Here is some additional reading that those that want to breed reptiles should consider.
Link

i entirely agree with that last paragraph and think that that should have been your first post even if you still ask why he was breeding the lizard. However to continue a conversation on genetics:

1.Is it wrong to breed the animal to see if the offspring carry the trait or even signs of it being recessive? (i have my opinion whats yours)
2.I more closely read the description of the tail..i still want to see a pic i keep envisioning rings so close that they look like waves. Some tails are shorter but can become very fat, and a 3yro leo that ways less than 50g may be screaming "i have potential" or it may be saying "I'm defective" it needs a trained eye or mind to judge i think.
3.If it is genetic it may not be a mutation. It's possible both parents carry the alleles for the compressed accordion but do not produce it very often. Fortunately most genetic combinations are not nearly as simple as het, co-dom, and recessive; most are far more complex than that and many "random" outputs from those are viewed mutations because who wants to do a microsatellite or allele marker study on every different thing that pops up. If it is a mutation then yes it is genetic, but that does not make it inheritable as a phenotype or even a genotype, however, it is possible. A mutation would increase the allele diversity of a population, and where wc's are so rare as you mentioned what more could one ask for to "strengthen" genes.
4. As important as it is to cull bad offspring there is something to keep in mind. As herpetaculturist we are creating sub populations that will not be nearly as selected for or against in the natural order of things as they would in the wild. In general sub-populations will decrease the allele frequency and will create different outputs than that of the main. this is especially true in our case where we actively select. The subpopulation may have trouble or it may flourish. Mutations may be removed quickly or begin to dominate the genetic bank. What is desirable to us may not be to the animals health, and what isn't may be (eg. albinism). At this point i can not say that this tail thing is either. We view the perfectly healthy form as the wild one simply because it exist but it is also continually evolving and therefore is not perfect by any means of measurment.
5. Could be that some myomeres didn't separate at the usual intervals during tail development which may or may not be a genetic issue, however, offspring may shed so light on that. Realizing of coarse, as always, to be ready to terminate poor results or remove then physically from the gene pool.
p.s. This has turned into one of the best threads I've been involved with for a long time.

Just to add information... What I know:
The geckos were purchased from two completely different breeders; I have to assume they are not siblings. I will include an older picture of the male in this post. The animal was purchased by my ex gf because she thought the animal was "cute." Again, the breeder did not specifically say that the tail abnormality was genetic, but only that the gecko had always had the shortened tail, and that it was not the result of tail loss. I should also mention that this gecko was not purchased for any kind of breeding program. It was purchased as a pet, and ended up being party of a HOBBY - one that does involve responsibility - This I understand. If I had any real reason to think that this was an abnormality that had any bearing on the health of the animal, I would not breed it again (and I haven't.) The animal is perfectly healthy, and I am more inclined to think that her size at the time of breeding was the factor in the poor production of eggs - and here we arrive at why I posted here in the first place. On the topic of this being a fault or defect, I would argue that albinism in the case of many of the animals being bred in the snake and/or lizard/gecko world would be an extreme detriment to their health if they actually lived in the wild, as their naturally developed camouflage is all but done for - however we consider these animals of value for aesthetic reasons. This gecko is not an animal that was born with weak bones or joints, or missing eyes. Philisophically I don't know where the line has to be drawn, because I suppose the same argument for the aesthetically pleasing albino could be given for an animal missing an eye... but I would bet that most of us feel that there is a difference, and I do not think that this tail abnormality is the equivalent of an animal missing an eye. Again, I will do my best to get a picture up today of the tail.

Thanks,
-and yes, this has been a very quality post.

Just to clarify i do realize that albinism is not near as detrimental in captivity and is considered ascetic. That was why i used it as an example of what is or is not detrimental when it comes to selective breeding, much like this mystery tail.

np