Posted on 02/15/2005 7:12:00 AM PST by furball4paws
Laboratory Speciation in Helianthus Evolves a Native Species
DNA examination of five species of Helianthus (H. annuus, H. petiolarus fallax, H. anomalus, H. paradoxus, and H. deserticola) suggested that H. annuus and H. petiolarus fallax are the evolutionary parents of the other three species (Rieseberg 1993, 1995, 1993). All five species are self-incompatible and fertile. Typically, H. annuus (the ancestor of the commercial sunflower) and H. petiolarus fallax form hybrids that are almost fully sterile. However, the few fertile hybrids, when subjected to sib-matings and back crossing regimes yield a new species that is fully fertile and cannot cross with either of the parental species. This new species is virtually identical to H. anomalus. The produced species is genetically isolated from the parents by chromosomal barriers. "Under laboratory conditions these changes are repeatable across independent experiments" (Niklas, p.64). The laboratory derived H. anomalus readily crosses with the native H. anomalus. Results indicate that H. deserticola and H. paradoxus may also have arisen via hybridization of H. annuus and H. petiolarus fallax. These two species have different synthetic capabilities from the parents and live in sandier and drier soils. Hybrid speciation may be common in plants where hybrids often form (see Gilia sp., Grant, 1966, Stebbins, 1959, Arnold, 1995), but is presumed rare in animals where hybrids are less common (however, see the minnow Gila seminuda, Bellini, 1994). Experiments to confirm the evolutionary parents of H. deserticola and H. paradoxus have not been performed. 1. Based on nuclear and chloroplast DNA analysis results, the Theory of Evolution predicts that H. annuus and H. pertiolarus fallax are evolutionary ancestors of H. anomalus, H. deserticola and H. paradoxus. 2. Hybrids of H. annuus and H. petiolarus fallax subjected to different regimes (at least 3) of back crossing and sib-matings, all converged into a new plant species with "nearly identical gene combinations" (Rieseberg) as the native species H. anomalus. This confirms the natural evolutionary parents of H. anomalus as predicted.
References 1. Arnold, J and S.A. Hodges. 1995. Are Natural Hybrids Fit or Unfit Relative to Their Parents? Trends Ecol. Evol. 10:67-71. 2. Bullini, L. 1994. Origin and Evolution of Animals by Hybrid Animal Species. Trends Ecol. Evol. 9:422-6. 3. Futuyma, D.J. 1998. Evolutionary Biology. 3rd. Edition, Sinauer Associates Inc., Sunderland, MA. 4. Grant, V. 1966. The Origin of a New Species of Gilia in a Hybridization Experiment. Genetics 54:1189-99. 5. Niklas, K.J. 1997. The Evolutionary Biology of Plants. Univ. Chicago Press, Chicago, IL. 6. Rieseberg, L.H. 1995. The Role of Hybridization in Evolution: Old Wine in New Skins. Amer. J. Bot. 82:944-53. 7. Rieseberg, L.H., and N.C. Ellstrand. 1993. What Can Molecular and Morphological Markers Tell Us About Plant Hybridization? Crit. Rev. Plant Sci. 12:213-41. 8. Rieseberg, L.H., B. Sinervo, C.R. Linden, M. Ungerer and D.M. Arias. 1996. Role of Gene Interactions in Hybrid Speciation: Evidence from Ancient and Experimental Hybrids. Science 272:741-44.A
Nice, neat, repeatable and meets all scientific criteria for a definitive experiment.
Bzzzt! Wrong!! Instead, would be a fish giving birth to a moose. (Bullfrogs being close to water are not suitable for this type of argument). The species may be too similar.
Right. Same "kind." (Whatever that means.)
"Get back to me when you can show a fish giving birth to a bullfrog"
Finally the subject gets back to Barbara Boxer
"A new species was obtained from the crossing of two separate species. I am sorry that is the definition of evolution."
No, it is not classical Darwinian evolution it is plant hybridization. However, you go ahead an interpret it as you chose - you will anyway.
However, like I said before - stop wasting bandwidth with posts that are only done to insult and irritate others.
The creos will ignore this post so they can come back later and make claims it refutes.
10 seconds to a bah-bull quote.
"Finally the subject gets back to Barbara Boxer"
Finally something funny and worth reading.
I relaize that this stuff isn't an easy read for most people, but one does have to read it.
This new species produced in the laboratory, testing the ToE, produces a new species. This "new" species is the same as a naturally-occurring, native species. This experiment shows how a native species could have (and probably did) arisen/arise. It is an experiment of a kind that is not often available in studying evolution.
BTW a moose is too close to water too, How about a camel?
most likely innovative selection from earlier speciae - all the way back to the Causa Prima.
I am sorry you are irritated and insulted. May I suggest a nice relaxing massage?
Clearly another case of wishful independent thinking.
"I am sorry you are irritated and insulted. May I suggest a nice relaxing massage?"
No, but you can explain to the admin moderator why you are intentionally attempting to pick a fight.
If they expect people to believe we evolved from slime, they need to do better than this! Where are the intermediates and fossils? They can talk about the origin of species all they want, but they should be trying to figure out the origin of phyla.
How did we get moved to the smokey backroom?
Perhaps a time-out would be more in keeping with his attitude?
It just one of the many mechanisms of evolution, and this study is not limited to simply hybridization.
Did you ever notice that the Cretinoids never seem to have a sense of humor? Must be some evolutionary trait that got eliminated via all that backwoods inbreeding.
Well, so far I've heard that this isn't evolution, that we need to prove we came from slime, that hybridization proves nothing and that I am trying to start a fight.
These experiments are nice and tight, so they can't complain there. They are also not Earth shattering, just another nail in the coffin.
I've been as nice as I can be and you guys have tossed out some worms.
Oh well - par for the course.
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