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Why current breeding practices are a failure.

This is a discussion on Why current breeding practices are a failure. within the Laws/Legality and Ethics forums, part of the Herpetological Science & Politics category; Some of you might already know that i oppose the breeding practices that dominate our hobby and that i have ...

Laws/Legality and Ethics Discussion of the laws affecting herpetology around the world. Species legalities in different jurisdictions, import/export of animals, the legalities of species collection and the ethical considerations of all of the above.

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Old 7th August 2013   #1 (permalink)
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Default Why current breeding practices are a failure.

Some of you might already know that i oppose the breeding practices that dominate our hobby and that i have tried in the past to explain why they are a failure in the long term and furthermore, why they are inmoral.
I thought i should try to be a bit more pro-active about it and make a post laying out a basis for the reasons why this is the case in the hopes that more people will understand the consequences of these actions and why we should try to change this aspect of how our hobby behaves. However, let me point out from the very beginning that this is in no way the whole story, just some of it.

First of all iīd like to present some important phenomena that are necessary to understand the possible ramifications of the current situation.

The first one is the phenomenon known as genetic drift. To put it simply, genes that are not subjected to selective pressures, mutate freely and drift largely at random.
If a gene is subjected to selection, mutations that modify it in such a way that the phenotype it produces in an individual is at a disadvantage, are selected against and elminated from the gene pool whenever they appear. This is what lies behind the principle of survival of the fittest (where fitness is defined as whatever increases survival and reproductive success in a particular context).
In captivity, the vast majority of selective pressures are eliminated or greatly reduced. Animals donīt have to compete with others for food, donīt have to evade predators, may not have to compete for mates and may even not need certain metabolic routes because their diet in captivity is consistent and sufficient to meet their needs of certain vitamins and other compounds.
Since these means that entire sets of genes are therefore not subjected to selection (or the pressures are hugely reduced), these sets of genes are then subject to genetic drift. Mutations acumulate freely because the deleterious effects are trivial in captivity. The survival of the animals is not significantly affected because we adapt to their needs.
This means that captive populations, over generations, may loose entire genetic complexes or gain variations that would not be adaptive in the wild.

The second phenomenon that is highly relevant is genetic association or genetic linkage. Some genes are associated to others, or even entire groups of others. Their inheritance is largely associated because of their possitions in the chromosome. Put simply, genes that are close are more likely to be inherited together.
This means that one phenotype may be inherited in association with other phenotypes. If one or more of those phenotypes is problematic, like a genetic disorder, selecting for a desired phenotype may well imply selection for its associated companions.

The third phenomenon is more specific and it is the active selection for deleterious mutations. Mutations that affect the expression of certain genes can produce new phenotypes which are highly prized by the majority of people in our hobby. Phenotypes of various types such as albinism, hypomelanism, hypermelanism, leucism, etc, are the result of mutations that modify the expression of pre-existing genes. In some cases they modify the degree of expression, their distribution and in others they stop the expression of certain genes.
When we consider pigments such as the various types of melanins, for example, this can be a serious problem because of the negative effects that supressing or diminishing the expression of some of these mollecules can have on the development of neural systems. This is because some of those mollecules are actively implicated in the development and function of the nervous systems. Mutations that affect the expression of this family of compounds can therefore in some cases have effects on the development of the nervous system to varying degrees. This is believed to be the cause of neural disorders in hypomelanistic mutations such as the spider morph in ball pythons or the enigma morph in leopard geckos.

Having pointed out these phenomena, i hope itīs clear that they are significant in the welfare and the future of captive populations.
Our hobby is very clearly dominated by a perspective that focuses almost obsessively on the production of new and rare variations of any kind. The motivations are two fold: commercial interests and the perception that new forms are valuable either because of their aesthetic qualities or their rarity.
This is of course not a new phenomenon among captive populations. Artificial selection has been part of human culture for a very long time, but while originally it was mainly oriented towards practicality, it became all about aesthetics in more recent times. From the victorian era and the obsession with dog breeds to current times and the massive production of morphs of various species, the pursue of form and aesthetics has been the dominant goal in the breeding practices applied to almost every captive population in connection to the hobby of keeping animals.
This has had consequences for these captive populations, in some cases extreme. The species that have been subjected to this particular brand of aesthetics based artificial selection for longer are the ones that have paid the highest price (dogs, pidgeons, poultry, canaries...).
In some instances, the pursue of new variants is quite neutral, since the variants themselves are natural polymorphisms that have no direct or associated effects on the individuals that carry them. In other cases, though, the desired variants are associated to problems or are problematic themselves. Sometimes, as is the case with brachycephaly in many dog breeds, the desired traits are actually severe deformities.
The fact that people are capable of desiring such traits in their animals is profoundly inmoral and extremely worrying, even more so because often times people are completely blind to the facts of what these traits imply. The willingness to ignore or downplay the effects of such traits is what drives the continued quest for the next one and the perpetuation of the already existing ones.

So as a consequence to all this, the reality is that currently, the vast majority of breedings of many, many species, are either randomized, meaning that there is no explicit selection whatsoever (and therefor that fitness is not a factor), or that the only selective criteria applied are oriented towards the production of variants of some kind or another.
In the light of the previously explained phenomena and the effects of both lack of selective pressures geared towards general fitness and the application of selection based solely on aesthetics and rarity, i hope itīs clear that the current system has only one possible outcome if it continues to exist as it is: the empoverishment of genetic fitness of all subjected captive populations and the purposeful acumulation of deleterious traits.

As i said in the beginning, this is nowhere near a complete description of the failures of current breeding practices, but i hope it will serve to inform and to raise consciousness about the importance of changing the obvious flaws in how things are being done for the sake of our animals and their future generations.



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Last edited by Azhael; 7th August 2013 at 19:35.
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Old 7th August 2013   #2 (permalink)
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Default Re: Why current breeding practices are a failure.

What do you mean by "failure"? At what do we fail?

It is a fact, that people try to breed as much as possible, and they tend to select any color morphs, but what does that change? Hardly any of the animals from pet trade and other genes that occur inside the "captive biosphere" are ever going to participate in breeding of natural populations.
More experienced mass breeders (at lest of natural forms) select the strongest and healthiest animals to continue breeding or sell/give them to other breeders, while "average" and weaker animals usually go to the smaller keepers who don't make big breedings, if they breed the animals at all.
And problems you mentioned probably don't touch scientific introduction-breeding programs.



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Old 7th August 2013   #3 (permalink)
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Default Re: Why current breeding practices are a failure.

I didnīt mention breeding programs or reintroduction efforts at all, Yanusz, it wasnīt even remotely part of the topic. Of course i agree with you that captive populations of these "pet" species are separate from wild ones and will have no impact on that genetic pool.

It is a failure because itīs terribly shortsighted and it consistently produces suffering and an empoverishment in the quality of life of many animals.

The whole point of the post was to address exactly what the fact of people breeding as muchas possible and selecting every single variant, changes. The breeding policies that are applied are terrible from the standpoint of population management, long term sustainability and welfare.
My post is all about welfare of captive populations and their future as independent gene pools.
As for these experienced breeders you speak of selecting the best stock, thatīs just not true. I donīt mean to say it never happens, i know some people do try, although their criteria for what constitutes fitness is suspect and as you say it is more common when it comes to wild-types. However, these professional breeders are also responsible for selectively breeding traits that negatively impact the fitness and the welfare of certain bloodlines because those traits are commercially very profitable and highly sought after by the hobbyists. Their breeding policies are not so much about guaranteing quality for their costumers but rather about maximizing production for themselves. How can i credit a breeder with caring about selecting fit individuals when they are producing deleterious phenotypes on mass? Just because they occasionally do something which is "not that bad" iīm not willing to obviate everything else they do.
The "weak" animals are bred frequently because of the very widespread inclination for people to breed anyting they buy in the hope of making some money, no matter what the animal is or the genes it carries, and even if they have to create hybrids. Thereīs just no control whatsoever...no ethics...just the drive to make a quick buck.



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Old 7th August 2013   #4 (permalink)
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Default Re: Why current breeding practices are a failure.

You should quit the forum if you feel that way and euthanize any animals you now have.



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Old 7th August 2013   #5 (permalink)
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Default Re: Why current breeding practices are a failure.

Would you care to explain why? I donīt have any species from any bloodlines that have been in captivity for very long, i keep no colour variants nor to my knowledge any animals that are heterozygous for any such variant and i try to apply some degree of selection to any offspring i produce.
So do you have an actual argument or critique you would like to make or is abuse and nonsense all you have to offer?



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Old 7th August 2013   #6 (permalink)
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Default Re: Why current breeding practices are a failure.

How would you suggest captive breeding be done then?



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Old 7th August 2013   #7 (permalink)
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Default Re: Why current breeding practices are a failure.

Travis, i donīt mean to imply that i have all the answers, because thatīs just not the case....at all... i just want to point out the facts of whatīs going on.
There are some things that i think can be done to improve the way we manage captive populations, and i would love it if others would chime in with suggestions.

Hugh, what a proud moment for you. So your argument is that itīs been done for a long time and thereīs no point in trying to change things? Iīm so glad there are people who donīt think the way you do or else we would still be living in caves or going around owning people as property.
Your personal attacks on me, while utterly hilarious, only serve to point out that you have NOTHING. Itīs great that all you have is an infantile assumption about my private life and an attack on my spelling, me being non-native and all.
I do understand the meaning of the word hypocrite, but the question is, do you understand why you are wrong?
Hereīs a hint: Those are not the practices used on the very caudates i own.



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Old 7th August 2013   #8 (permalink)
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Default Re: Why current breeding practices are a failure.

Quote:
Originally Posted by Coastal Groovin View Post
You should quit the forum if you feel that way and euthanize any animals you now have.
Why? This forum is not dedicated to captive breeding, nor to particular breeding practices [desirable or otherwise]. You should note that this thread is in fact in a section on ethics and legality, a subsection of "Science and Politics".

To some degree, I agree with the OP. However, there are aspects of genetics, selection, and fitness which do not necessarily support all of his assumptions and conclusions.

For example, in captivity, natural selection pressures do not disappear. Rather, they change somewhat in format. Those pressures are imposed by the content and timing of the foods we offer; the chemistry and temperature regimes of the water we provide; the light spectra, duration, and schedules we provide; the bacterial and parasite faunas present; the dimensions and populations of the environments we provide. These are all natural selective pressures which are uncontrolled byproducts of our husbandry practices.

Another factor is the basic nature of evolution with respect to cladogenesis and speciation. Specifically, most of the traits we use to identify species and higher taxa are probably NOT selective ones, but coincidental ones. Color, scalation, and pattern for instance, are often highly variable within species as a consequence of mutation and lack of selection. When populations are divided, the resulting gene pools begin to collect differing sets of mutations. By the time a new species or genus has developed, these random traits developed in common have become diagnostic, even though not [or minimally] selective. Oddball color mutations, including melanism and albinism, might well be part and parcel of new species. Might not the colors of northern cardinals or of canaries, be the result of oddball color mutations? Such mutations could remain in the population for a long time, allowing other mutations to correct for any problems they cause. These mutations might not be all that deleterious either, given how common albinos can be in nature [mostly in terms of the numbers of species, not individuals] which have them. The albino salamander I found was an adult, implying that survival was not strongly impaired by the mutation. Some populations of tiger salamanders are noted for the frequency of albinism, which again might not be a problem for a nocturnal and fossorial species.

However, it's absolutely true that private breeders [or their businesses] are fairly constantly "unethical" by definition of this thread. Many questionable practices are not just widespread, but virtually ubiquitous. Almost anyone who obtains a unique mutation will proceed to breed and select for the trait, and then market it, regardless of their past history of 'healthy' breeding. Despite about 1000 species of salamander, many thousands each of lizard, snake, and frog, many hybrids are created or are already produced. Hybrids are created because a) breeders don't know or care if they have a "pure" lineage, breeders want one or more traits not found in a single species, breeders want something new and marketable, etc. Look at the number of operations which do not advertise multiple species, but countless color forms [pure or hybrid] of a single "species". Does ANYONE breed locality ball pythons or bearded dragons? How many producers do we really need for albino or GFP axolotls, fantasy horned frogs, tiger carpet pythons, ball pythons, or bearded dragons? These are a good cross-section of the hobby, consisting as they do of the vast number of amateurs looking to produce something...ANYTHING, for a buck. When you consider the less numerous 'expert' or advanced breeders...they're the ones who CREATE the hybrids and mutant strains in the first place. Those who do not are probably a terribly small percentage made up largely of those who simply haven't had the luck to get a new mutant.

Quote:
Get off your high horse with your rambling diatribe about breeding animals...
Such a blinkered and uneducated response isn't even worth addressing.



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Old 7th August 2013   #9 (permalink)
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Default Re: Why current breeding practices are a failure.

I have removed the offensive post fro, Hugh to which FrogEyes and Rodrigo refer. I have invited him to re-post without the inappropriate parts of hismessage.

C



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Old 7th August 2013   #10 (permalink)
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Default Re: Why current breeding practices are a failure.

Bill says so because he's angry at entire world for hating him.

Well, you say lack of natural selection is bad? We humans are also mostly avoided by it. I don't see anybody saying "it's bad to heal sick people, if they're fit, they will survive." These animals are in fact a part of our civilization since we keep them at our homes. The fact that you keep them at home makes it unnatural and gives them too much chance of survival. What do you call "some degree of natural selection".
From one side you say you don't keep anything that is a long-term captive bloodline, from the other - you are against WC animals. Where's logic here?

And it does look obvious to me, that if i were a mass breeder, i would keep the stronger, bigger, healthier animals as breeders simply because they present a bigger potential of breeding lots of offspring which give meh moar monies.

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Old 7th August 2013   #11 (permalink)
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Default Re: Why current breeding practices are a failure.

The sad fact is that you would have to raise and sell an awful lot of healthy wild type axolotls to make the same kind of money that one piebald one (like the one on the front of the tfh book) would sell for. The buyer would probably not know or care that it would be dead from skin cancer in a year or two. The average pet axolotl would be dead from poor water quality or starvation anyway in that amount of time anyway.



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Old 7th August 2013   #12 (permalink)
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Default Re: Why current breeding practices are a failure.

Quote:
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The first one is the phenomenon known as genetic drift. To put it simply, genes that are not subjected to selective pressures, mutate freely and drift largely at random.
This is not genetic drift based on my admittedly meager scientific knowledge, so please correct me if I'm wrong. Genetic drift is the change in allele frequency within a population due to either the bottleneck effect or founder effect. Both actually lowers genetic diversity. The founder effect is when a small population of the main population leaves and forms a new colony elsewhere, thereby becoming the founder group of this new population. Since the individuals of the founder group are largely random, the allele frequency of the newly founded population will likely misrepresent that of the original population. One allele will likely be overrepresented compared to its counterpart, or some alleles may not be represented at all, thereby lowering genetic diversity. In pet hobby, the groups of animals taken from the wild can be thought of as founder groups. Theoretically, this means that the collective population of animals we all keep, including WC individuals and those captive bred from WC individuals, is likely low in genetic diversity.


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This means that captive populations, over generations, may loose entire genetic complexes or gain variations that would not be adaptive in the wild.
If selection is so low or even nonexistent, then specific alleles or genetic complexes should not disappear completely, since there is no mechanism selecting against them. However, new mutations that would not be adaptive in the wild will also not be selected against. This, combined with the aforementioned founder effect, will likely result in a population whose genetic makeup differs strongly from that of wild populations. But I can also see the other side of the argument, which is that these animals will not be released into the wild, at least shouldn't be. They will continue to live and reproduce because like you said, hobbyists and breeders will cater to their needs, this will not do them any harm. The only problem with this may be if somehow, captive populations are used for reintroduction projects. The probability of this I do not know. I can see both sides.



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Default Re: Why current breeding practices are a failure.

Quote:
Originally Posted by Azhael View Post

The second phenomenon that is highly relevant is genetic association or genetic linkage. Some genes are associated to others, or even entire groups of others. Their inheritance is largely associated because of their possitions in the chromosome. Put simply, genes that are close are more likely to be inherited together.
This means that one phenotype may be inherited in association with other phenotypes. If one or more of those phenotypes is problematic, like a genetic disorder, selecting for a desired phenotype may well imply selection for its associated companions.
This is possible and can obviously be terrible. However, not all genes associated with the desired phenotypes are necessarily detrimental to the animals health, so it may not be fair to demonize this practice completely.



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Default Re: Why current breeding practices are a failure.

The same thing is happening with the human race; its known as "human gene deterioration" or "human devolution". The "perfect" society that we have created has allowed us to have high survival rates despite any negative mutations that developed. So, as population increases and thrives, people are born with more and more mutations. Because of this, it is thought that we aren't evolving anymore, but possibly even devolving. Sorry a little bit off-topic but I see how this greatly compares to captive animals. Captive animal genetic deterioration would happen much faster than that in humans, because captive animal populations are significantly lower.



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Default Re: Why current breeding practices are a failure.

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Originally Posted by JoshBA View Post
The same thing is happening with the human race; its known as "human gene deterioration" or "human devolution". The "perfect" society that we have created has allowed us to have high survival rates despite any negative mutations that developed. So, as population increases and thrives, people are born with more and more mutations. Because of this, it is thought that we aren't evolving anymore, but possibly even devolving. Sorry a little bit off-topic but I see how this greatly compares to captive animals. Captive animal genetic deterioration would happen much faster than that in humans, because captive animal populations are significantly lower.
Sorry, but that is nonsense.

Despite what people may "believe", humans are currently evolving about 10000 x FASTER than the normal background rate. This has been the case for several thousand years at least. The human population now numbers roughly 7 billion, and the combination of large numbers and reproduction is what drives evolution. This combination creates not only a vast number of new mutations [estimated at an average of 100 per person], but a never-ending mix of those mutations. Evolutionary novelties derive not simply from single mutations, but from the interactions of multiple mutations. A consequence of this is that an allele which is deleterious on its own may become advantageous when combined with something else. Malaria-resistance is one example of this, as each allele alone is potentially fatal under some conditions, but advantageous when combined. If a mutation duplicates this gene, malaria resistance could become 100% in a population while sickle cell anemia simultaneously declines to 0% [compared to the current situation, which should be 50% healthy and resistant, but at the cost of 25% each susceptible to the diseases]. Autism spectrum could be another example. In this latter example, it is likely that multiple genes are involved already, with the 'upside' being many individuals who have exceptional mental skills of one sort or another.

It's not a simple case of "breeding a generation of idiots". It just doesn't work that way. When it seems so, I'd wager it has a lot more to do with education [or lack thereof] and a prevalence of religious or political indoctrination.

Another point of fact is that many animals actually show NO sign of genetic depression in captivity. Amphibians chief among the examples. Where issues exist, it's largely because we have made concerted efforts to line breed the worst traits into single breeds.

Last, there is no such thing as "devolution". That's nothing more than a talking phrase for those whose agendas involve denial of evolution in the first place. Evolution has no direction - it is simply change and inheritance. If selection is driving those changes in a particular direction, it's because selection is favoring what is slightly more positive and denying what is slightly more negative. Nature may not agree with us as to what is truly 'best'.



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Old 8th August 2013   #16 (permalink)
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Default Re: Why current breeding practices are a failure.

That is a very interesting point.



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Old 8th August 2013   #17 (permalink)
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Default Re: Why current breeding practices are a failure.

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For example, in captivity, natural selection pressures do not disappear. Rather, they change somewhat in format. Those pressures are imposed by the content and timing of the foods we offer; the chemistry and temperature regimes of the water we provide; the light spectra, duration, and schedules we provide; the bacterial and parasite faunas present; the dimensions and populations of the environments we provide. These are all natural selective pressures which are uncontrolled byproducts of our husbandry practices.
I admit i wrote the post in a single seating and i probably should have taken more time to make sure that i was clear. There were a number of concepts that i only touched on superficially and i also realize now they probably arenīt at all obvious in connection with one another.
I most certainly did not mean to imply that ALL selective pressures disappear but i can see that my use of the words "vast majority" was misleading and exagerated. Rather, some of them do and others are significantly palliated. Furthermore, new pressures or new versions of them can appear as you have pointed out.
Selective pressures certainly exist, and must always exist, in any kind of environment, but the ones that captivity supplies are different in many ways than the ones that wild populations are subjected to. That was meant to be my point.

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Oddball color mutations, including melanism and albinism, might well be part and parcel of new species. Might not the colors of northern cardinals or of canaries, be the result of oddball color mutations? Such mutations could remain in the population for a long time, allowing other mutations to correct for any problems they cause. These mutations might not be all that deleterious either, given how common albinos can be in nature [mostly in terms of the numbers of species, not individuals] which have them. The albino salamander I found was an adult, implying that survival was not strongly impaired by the mutation. Some populations of tiger salamanders are noted for the frequency of albinism, which again might not be a problem for a nocturnal and fossorial species.
I had tried to account for this when i said "where fitness is defined as whatever increases survival and reproductive success in a particular context", however, as i said earlier, i realize the attempt was too superficial and too vague in connection to other statements to be successful in putting the point across. I should have taken the time to be much more clear.
Genes that are deleterious in one context (not just environmental but also genetic) can be advantageous in another. What they are in terms of fitness is determined by those factors.

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However, it's absolutely true that private breeders [or their businesses] are fairly constantly "unethical" by definition of this thread.
Since we are all dealing with living organisms, with nervous systems and the capacity to feel pain and suffer, i consider the matters of how they are kept and maintained to be moral issues. How we breed them, which traits we select for, etc, are an inextricable part of it.




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Well, you say lack of natural selection is bad? We humans are also mostly avoided by it. I don't see anybody saying "it's bad to heal sick people, if they're fit, they will survive." These animals are in fact a part of our civilization since we keep them at our homes. The fact that you keep them at home makes it unnatural and gives them too much chance of survival. What do you call "some degree of natural selection".
No, Janusz, i said that the suspension or mitigation of some selective pressures can result in genetic drift which CAN have negative effects. We humans are indeed also affected by the same phenomenon and there are consequences to it. My myopia and my bad back are mild examples of this. Myopia in particular is an utterly trivial trait in many societies...my life isnīt impacted negatively by it in any significant way. However, in different circumstances, it could have meant a very severe disadvantage. The acumulation of "defective" genes such as these in human populations is the result of our increasing quality of life which allows for the survival of previously "unfit" individuals and the perpetuation of the underlying genes. This is WONDERFUL for the individuals, but has consequences for populations. Some of these consequences are being addressed by things like genetic therapy nowadays, for the benefit of future generations.

What i mean by it is, i think, fairly obvious. I allow larvae to compete, i tend to not overfeed these days and if any offspring survives despite having some kind of mild deformity or impairment, i try to make sure they go to individuals who will keep them as pets, but who donīt intend to breed with them.
Iīm not claiming this replicates any natural context, but it is something.

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From one side you say you don't keep anything that is a long-term captive bloodline, from the other - you are against WC animals. Where's logic here?
O_o This has absolutely nothing to do with the topic and i have addressed the matter before in other threads. If you like i will again, but not here.

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And it does look obvious to me, that if i were a mass breeder, i would keep the stronger, bigger, healthier animals as breeders simply because they present a bigger potential of breeding lots of offspring which give meh moar monies.
Yes, iīm not saying i donīt understand the way the market works, what iīm saying is that since we are dealing with living organisms, there are ethical issues to consider that should have preference over people wanting moar monies. It does in other areas that involve animals (although insufficiently so, in my opinion), our hobby should be no exception.




Stanley, what you describe is indeed the bottleneck effect. Genetic drift is a different phenomenon and is basically what i described, whoever clumsily.
The bottleneck effect is another relevant phenomenon that i didnīt get into, so thank you for bringing it up. It is yet another factor that should be considered in the management of captive populations.

Genes can disappear completely or be modified by drift. Mutations can occur that change them, or even, as i say, eliminate them entirely and this mutations can survive in the gene pool because their effects are trivial in the set of selective pressures that captivity provides.

No, that wouldnīt be the only problem. In fact, supossing that any of these captive populations will remain independent of the wild ones, this wouldnīt be a problem at all. The real problem is the acumulation of deleterious mutations, either randomly or purposefuly, which impact animal welfare. I mentioned earlier brachycephaly in some dog breeds. That is a very serious problem in itself, wether the genes make it into wild wolf gene pools or not.

Finally, i didnīt mean to demonize the entire practice by the phenomenon of genetic linkage alone, because as you and i both have said, not all alleles are associated to detrimental companions. I mentioned it because itīs a relevant concept to understand in connection with the others. The first two phenomena i described are natural phenomena that happen independtly of our breeding practices, but they are relevant nontheless and i think itīs useful for people to be familiar with them.
The acumulation of one of the phenomena, on top of the other, on top of the other, on top of things that have been left unmentioned, is what ultimately causes a dire situation.



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Last edited by Azhael; 9th August 2013 at 23:56.
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Old 8th August 2013   #18 (permalink)
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Default Re: Why current breeding practices are a failure.

Josh, as FrogEyes has pointed out the idea of "devolution" is an utterly nonsensical one.
ANY change in the genetic frecuencies in a population over time is evolution, wether it implies the acquisition of new genes, the modification (adaptive, neutral or deleterious) of existing ones or the loss of one. You canīt devolve, you can only evolve. Devolution would require time travel xD
Furthermore the only way we could stop evolving is if reproduction stopped altogether. As long as it continues, our populations will evolve.
Those are common misconceptions which are unfortunately made popular by interested parties, but they are complete nonsense.

Anyway, this is all quite off-topic (and likely to open an epic can of worms), letīs bring it back to the original subject please.

Quote:
Another point of fact is that many animals actually show NO sign of genetic depression in captivity. Amphibians chief among the examples. Where issues exist, it's largely because we have made concerted efforts to line breed the worst traits into single breeds.
Correct me if iīm wrong but i would atribute this largely to the fact that amphibians as a group are relatively new to the game and have been subjected to selective breeding for far less time than other groups. Another significant factor is almost certainly the fact that the influx of wild animals into the hobby has and sometimes continues to be, very large. Their hability to reproduce explosively might also have something to do with it.
However, as you say, there are examples of things going badly in some species or some specific bloodlines, and this trend is growing. Itīs precisely because i expect the trend to continue and eventually throw many captive amphibian populations in the direction of whatīs happened to ball pythons or leopard geckos, that i think efforts should be made to improve things before they get as bad as that.
I suspect some axolotl bloodlines as well as some Ceratophrys and Xenopus ones are the worst examples of genetic depression to be found among captive amphibians.

So far, amphibians have been far less affected than other groups and may even have not been affected in any recognizable way at all in many cases, but how long will that last?



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Old 8th August 2013   #19 (permalink)
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Default Re: Why current breeding practices are a failure.

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O_o This has absolutely nothing to do with the topic and i have addressed the matter before in other threads. If you like i will again, but not here.
Sorry but i don't really follow this forum (since most of the most experienced keepers have left it) and i don't check out most threads. In fact i came by this one accidentally.
Your statements have to do with the topic, simply because when you talk about degeneration of captive animals, an answer is a thing called by breeders "adding new/fresh blood". And the best way to add fresh blood is adding wild animals to a captive group.

Well, in conclusion i can only say that there are always going to be "stronger", more hardy races even when weak mutants looking not much like their wild ancestors will be at the top of their popularity (as same is with dogs, cattle etc.), there are always breeders who keep "classic" ones, i see this with newts, guppies etc. I'm the one who prefers wildtype animals and don't try to keep my newts under sterile conditions that weaken them with time and there are others like me.

Ah, and slightly aside of the topic, some people should understand that promoting keeping axolotls in absolute sterility, adding salts, overfiltering the water and saying that putting in their thanks anything that wasn't previously baked, boiled and washed with 10 types of desinfection means will do nothing but boost the process of degeneration, IMHO.



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Old 9th August 2013   #20 (permalink)
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Default Re: Why current breeding practices are a failure.

I am pretty new to Caudata.org. I love the conversation and I love the debate about genetics. But it seems like alot is being assumed about how people are caring for and breeding their amphibians.



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