Ok, I must say, the replies in this thread confuse me greatly, especially as far as the reasons for opposition to these (or any) hybrids.
First, several people mentioned the cash motivation as a mark against them. I just got back from the last Daytona expo, and if breeding something for cash is somehow wrong, the price tags sure didn't reflect that. Especially that albino GTP for $100k. Aside from the fact that plenty of morphs and rare species command attention and high prices for precisely the same reason, why do the motivations of the keepers matter to the animal? If I breed an animal for money or for the fun of it, does the animal know the difference, and is there a difference in the animal's health? No. Objecting to the cash incentive is fine, but that should not be confused with the merits/flaws of a particular breeding project's offspring in and of themselves.
Secondly, some of the reasons given seem very subjective. Some of you simply say "it's wrong" without giving any reason, while others have specific objections, and I'll address a few below:
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I see no reason to fight the laws of nature. What are the chances a ball and a blood will ever meet in wild? Not in our life times.
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The current distinctness of the species genepools should not be construed as indicative of the future. As we all know, at one point they shared a gene pool via their common ancestor, and, more to the point, they may combine again in the future. Several species of Abystomatid salamaders and
Cnemidophorus lizards are actually the result of hyrbidization between distinct parent species. IIRC, Ambystoma jeffersoni is even tetraploid (containing 4 copies of each chromosome) as a result.
In fact, one of the profs in my dept is actually seeing the same happen with one of the icons of evolution, Darwin's finches. During an extended drought in the galapagos, the large-beaked species began hybridizing with a smaller beaked species (something it does not normally do). Once the drought ceased, the hybridization ceased, but had it continued, two species might have collapsed back into one.
Furthermore, much of what we do in captivity in unnatural, including all morphs (albinos are usually eaten by predators pretty early on), so 'natural' is rather a tenuous objection.
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Snakes have went through many many years of evolution to get where they are now. By creating hybrids, we are forcing them to start the adapt to survive deal all over again, for what? So we can make a good dollar? No good reason if you ask me.... I mean herps have developed all sorts of features and characteristics to help them survive where they live. Be it eyes on the top of the head in the anacondas to the black color of Marine iguanas to warm up quickly in the sun, they got these features for a reason.
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Well, since these are captive animals (which obviously should never be released into the wild), they don't need to fight to survive anyway. Additionally, as mentioned above, the natural hybrids of species can do quite well for themselves.
Most of the difference between species isn't adaptations, but rather traits randomly fixed by genetic drift, founder effect and other non-selective factors. The disadvantage suffered by a hybrid between two congenerics would be modest, if even detectable at all.
Consider, for instance, the difference between king snakes and corn snakes. Sure, each is adapted to their own particular lifestyle, but each could also survive in the other's habitat (as legions of escaped pets do). They're different, but not *very* different (part of the same subfamily, colubrinae). Now, all of those differences have taken over 20 million years to accumulate; all N.A. colubrid genera are present in the fossil record by early Miocene, concurrent with the widespread climatic shift during that epoch. 20 million years, and they can still produce viable hybrids (I've seen a few around), and aren't really *that* different.
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Wonder why so many hybrids are infertile, probably because its not meant to be.
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Meant to be? Nature doesn't have goals or intents. Infertility is the result of differing chromosome numbers, preventing proper meiosis. Some combinations have this trouble (mules), others don't.
Similarly, by that logic, many hybrids *are* meant to be, since they're not only fertile, but have hybrid vigor, a condition in which the animal grows larger and more powerful than one would expect from a simple mix. Examples of this are Chai Yai, the 20-foot hybrid crocodile at Sampuktran crocodile park, and ligers (the cross of a female tiger with a male lion).
Note: the next two are from two different posts, but are similar, so I'll adress them together.
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I see no reason to dirty bloodlines by doing this or most other hybrids. I would pay more for a pure blood herp than some nasty hybrid.
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and dirty genes than it's not worth it.
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"Dirty genes/bloodlines"? I've had more than my fair share of molecular biology classes in my undergrad and graduate education, and these concepts sound like something from before we discovered how genetics works.
Any two species which can hybridize are going to be 95% genetically identical, if not moreso. Within a genus, probably more like 99%. Heck, we're 98% identical to a chimp, and we've been separate for 5 million years, and aren't even in the same genus. Most of the genes that have changed have to do with things like skin color, gross morphology, and disease/parasite resistance (parasites and diseases play a much larger role in evolution than is often appreciated).
Remember earlier in this post, how I mentioned that many differences between species were non-selectively fixed by genetic drift and similar factors? That's what makes hybrids interesting: both parent species are homozygous at a particular loci, and by combining them, you can re-introduct that lost genetic diversity. Sometimes this is good, producing stronger, more powerful offspring, sometimes it's bad, but most of the time it has no major effect.
Personally, I've got a hyrbid in my living room. It's a plant, yes, but the genetic principles are the same: by combining the genes of two tropical plants which have different benefits, they were able to create one so vigorous and hardy it can grow as a houseplant.
Genes are not good or bad, unless they're lethal mutations (in which case, natural selection weeds them out pretty quickly). The "good" or "bad" effect, comes from the interaction of a gene with other genes in the genome and with the environment. Mixing two species gives them greater genetic diversity within a given individual, enhancing the likelyhood of beneficial interactions.
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Whatever you call them, there still is no good reason for breeding them together
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Here I must confess that what drew me to this thread was that my fiancee and I have been considering this very cross, and for a good reason: As many of you likely know, all US beardies originate from the population exported from AU before they stopped exports. This wasn't many animals, a few hundred at most, which created a serious genetic bottleneck, reducing genetic diversity. Further inbreeding for color has contributed to the damage, as has the fact that most beardies become pets, so only a few animals each generation contribute to the genes of next generation. This has become evident in smaller, weaker animals, more medical problems, and smaller clutches.
Rankin's, on the other hand, offer fresh genetic material from a closely related species. A hybrid between the two would introduce beneficial alleles which have been lost from the beardie population over the years, ideally resulting in stronger, healthier babies. If they're infertile, they'd be better pets anyway (healthier, longer-lived), if fertile, they could introduce long-since lost good genes back into the general beardie gene pool. Hardly a blatant cash grab, the motivation is to improve the genetic health of animals we consider to be excellent and loving pets. On the off-chance something does go wrong, they won't even be put up for sale; we're both very fussy about the genetic quality of our animals.
Additionally, I'm considering breeding a hybrid between two lizard species, one of which can regenerate an autotomized tail, the other of which cannot. Whether the hybrids can or cannot regenerate their tails, and genetic testing of these hybrids, could serve to elucidate the genetic basis of tail regeneration in lizards. The potential medical applications of this should be obvious.
I can appreciate why people would be concerned about the genetic health of hybrids, and like any genetic project, the breeding of hyrbids should involve extensive research into the genetic backgrounds and chromosomal configuration of each species, however, a lot of the arguements put forth in opposition in this thread appear to be subjective and not based on sound genetic reasoning.
Henry
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