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Natural Science Forum / Biology / Paleontology / April 2008Breeding more Dinosaur-like Chickens feasible in mid-term?
Hi, I am interested in opinions of a project I have in mind involving evolutionary development. As birds are more or less dinosaurs, more precisely decended from theropod dinosaurs and in the microraptor group, and that it is now knows that so-called junk DNA actually contains deactivated ancestoral genes and regulatory elements ( see: http://www.sciam.com/article.cfm?articleID=000E9965-99A6-13FB-99A683414B7F0000 and http://article.gmane.org/gmane.music.dadl.ot/38988 for examples of teeth and tail research in birds; sorry for the lack of links directly to the journal articles), one can assume that in the mid-term, modern molecular biology may elucidate and activate some of these genes. Aside from being a compelling piece of evidence for evolution (well needed in some parts of the world right now!), this would help us understand developmental embyology, give greater insights into the mechanisms of evolution, and most importantly, be insanely cool. With scientist currently working of the molecular biological techniques required to 1) halt the loss and fusion of the 15-17 vertebrae visible in the embryo into the Pygostyle (bird version of the coccyx) to from a tail, 2) induce the development of teeth, and 3) reengineer the wings into clawed appendages. All three of these projects seem to be making good progress, and all involve minimal changes in the DNA the subject organism, the domesticated chicken Gallus gallus. The chicken is the best possible organism to use in the proposed project; it is easily available in a wide variety of breeds, its eggs are applicable to many standard scientific methods in embryology, any techniques discussed in the previous paragraph could be immediately applied, and most importantly, it is one of the handful of organisms with a fully sequenced genome. So, I propose to in parallel to the scientific research currently underway, a seperate project is undertaken to breed in raptor-like characteristics in domesticated chickens, that can be latter combined with the already mentioned scientific techniques to generate a dinosaur-like phenotype. My suggestion would be to 1) breed back the chest musculature and pectoral girdle, and aim to breed forward the shoulder blades to a more primative raptor form. 2) aim to breed up the leg scales to cover the entire body (the reverse has already been done, the the naked neck chicken breed to be completely featherless, see: http://www.newscientist.com/article/dn2307-featherless-chicken-creates-a-flap.html). Further breeding aims may include breeding to a more raptor like pelvis, and for head morphology, however, this will probably only be possible after the development of the tail and teeth reseach, as these change will most probable affect the shape of the head and the animals balance, so premature breeding will be wasted. So, sorry for the long post, but I hope you found it interesting! please post any comments suggestions or advice! D. > Hi, > [quoted text clipped - 14 lines] > understand developmental embyology, give greater insights into the > mechanisms of evolution, and most importantly, be insanely cool. No. You mistake the nature of the experiments you cite. These are not the reactivation of long-dormant genes. If there were any long-dormant genes, they would long ago have mutated out of recognition because selection wouldn't have conserved them, there being no selection on dormant genes. Instead, these were genes that still have functions in living chickens, but are activated at different times and/or different places than in their ancestors. If you activate them in the ancestral times/places, you get ancestral morphologies. There are no fossil genes in the chicken. > With scientist currently working of the molecular biological > techniques required to 1) halt the loss and fusion of the 15-17 [quoted text clipped - 27 lines] > change will most probable affect the shape of the head and the animals > balance, so premature breeding will be wasted. Parts of this might actually be feasible. Though you would get merely a simulation of an extinct raptor, not a real raptor nor any real raptor genome. You'd just have a weird-looking chicken that resembled a primitive theropod. Note, however, that a scaled body would not be accurate, since the theropods you are trying to simulate were feathered. > So, sorry for the long post, but I hope you found it interesting! > please post any comments suggestions or advice! > > D. Thanks for the thought out reply! just a couple of comments: > No. You mistake the nature of the experiments you cite. These are not > the reactivation of long-dormant genes. If there were any long-dormant [quoted text clipped - 5 lines] > times/places, you get ancestral morphologies. There are no fossil genes > in the chicken. While its true that the project I mentioned themselves are not aimed at the recovery of long dormant genes, they aim to simulate their function; for example, there must have been a regulatory element to activate the growth of the embryonic tail, something that is now missing in modern birds. Also, there are ways to recreate long dormant genes; such as inference from multiple decendants of the target organism (http://icb.oxfordjournals.org/cgi/content/abstract/ 43/4/500), and there is no reason to think that this approach might not also be applicable to control elements, although theres aren't to many theropod decendants left to analyse! Also, although very unlikely, there is the possibilty that fragment of dinosaur dna might be recovered inside dinosaur bones, although the chance that this is discovered, and that it contains that required genes and control elements is vanishingly small. But either way, that purpose of the project is to create a dinosaur-like chicken, not to do the impossible. > Parts of this might actually be feasible. Though you would get merely a > simulation of an extinct raptor, not a real raptor nor any real raptor [quoted text clipped - 3 lines] > Note, however, that a scaled body would not be accurate, since the > theropods you are trying to simulate were feathered. As mentioned above, and in the title, the project is to create a simulation! A dinosaur-like chicken. And although you suggest weird looking, I might suggest awesome looking. Of course you are right about the feathers, I believe the current opinion is that t-rex had feathers as an adolescent; I just think scales are cooler :) Does anyone have even a vague idea on how many generation of selective breeding it would take to accomplish this kind of project? I am refering to the wing and shoulder relocation and feather replacement? And if not scales, does anyone have a good reference to the morphology of raptor feathers? > Thanks for the thought out reply! > [quoted text clipped - 15 lines] > activate the growth of the embryonic tail, something that is now > missing in modern birds. Yes, but you apparently misunderstand what a regulatory element is. It's not a gene. It's what is called a transcription factor binding site. These are short segmenets of DNA, usually in the upstream promoter region of a gene, that are easily gained and lost through a small number of mutations. They aren't dormant; they are either present or not present. Might I suggest you read a fine book by Sean Carroll, Endless Forms Most Beautiful? That will give you a grounding. > Also, there are ways to recreate long dormant > genes; such as inference from multiple decendants of the target > organism (http://icb.oxfordjournals.org/cgi/content/abstract/ > 43/4/500), No, not long-dormant genes. Ancestral genes, yes. But genes dormant that long would tend to be lost entirely or to have no remaining information about the ancestral state. You are right that if the gene had been deactivated recently enough we could recover a probable ancestor. At any rate, none of the evolution you are talking about is likely to involve dormant genes anyway, and so the idea is not relevant. > and there is no reason to think that this approach might > not also be applicable to control elements, Yes there is. Because they are so short, their information is more likely to be entirely deleted. > although theres aren't to > many theropod decendants left to analyse! Well, there are 10,000 or so, but they all descend from a single ancestor that had lost the functions you are interested in already. So, yes, that's another thing that makes reconstruction impossible. > Also, although very > unlikely, there is the possibilty that fragment of dinosaur dna might [quoted text clipped - 3 lines] > project is to create a dinosaur-like chicken, not to do the > impossible. And certainly that would be possible. >> Parts of this might actually be feasible. Though you would get merely a >> simulation of an extinct raptor, not a real raptor nor any real raptor [quoted text clipped - 13 lines] > breeding it would take to accomplish this kind of project? I am > refering to the wing and shoulder relocation and feather replacement? Selective breeding is going to take a very long time, and you might never get there at all. Genetic engineering is your best bet. > And if not scales, does anyone have a good reference to the morphology > of raptor feathers? Sure. Different feathers had different morphologies. Just consult the primary literature for the original descriptions of the species involved. Here are a few: Ji, Q., P. J. Currie, M. A. Norell, and S.-A. Ji. 1998. Two feathered dinosaurs from northeastern China. Nature 393:753-761. Ji, Q., M. A. Norell, K.-Q. Gao, S.-A. Ji, and D. Ren. 2001. The distribution of integumentary structures in a feathered dinosaur. Nature 410:1084-1088. Xu, X. 2000. The smallest known non-avian theropod dinosaur. Nature 408:705-708. Xu, X., X.-L. Wang, and X.-C. Wu. 1999. A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China. Nature 401:262-266. Xu, X., Z. Zhou, X. Wang, X. Kuang, F. Zhang, and X. Du. 2003. Four-winged dinosaurs from China. Nature 421:335-340. > Thanks for the thought out reply! > [quoted text clipped - 46 lines] > And if not scales, does anyone have a good reference to the morphology > of raptor feathers? They have just reported in the news that feathers from very early birds or near birds have been found in amber. Personally I'd stick to arms and tails with a beak on a more bird like animal about the size of chicken for people to use as pets. I don't want it eating the dogs or the kids. |
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