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Conservapedia talk:Lenski dialog (view source)
Revision as of 21:33, June 29, 2008
, 21:33, June 29, 2008→Lead author won't answer simple, basic questions
::::: ''"Reading Lenski's recent paper for comprehension reveals that the hypothesis being tested is that development of the Cit+ strain is a historically contingent process (that is, arising by multiple steps separated over time)."''
::::: ''"Reading Lenski's recent paper for comprehension reveals that the hypothesis being tested is that development of the Cit+ strain is a historically contingent process (that is, arising by multiple steps separated over time)."''
:::::I was aware that one of the original goals of the experiment was to test for historical contingency -- that was the reason for freezing the populations at each 500th generation. My questions were about other things: (1) was Cit+ evolution an original goal of the experiment (remember that this whole experiment started in 1988, long before the study in the present paper), (2) was favoring Cit+ evolution a purpose or one of the purposes of the glucose-cycling (giving the bacteria insufficient glucose supplies so as to cause alternating glucose feeding and starvation), and (3) what were other purposes -- if any -- of the glucose-cycling. Zachary Blount did not give a straight answer to the first question and gave no answers at all to the latter two questions. [[User:LarryFarma|LarryFarma]] 13:12, 29 June 2008 (EDT)
:::::I was aware that one of the original goals of the experiment was to test for historical contingency -- that was the reason for freezing the populations at each 500th generation. My questions were about other things: (1) was Cit+ evolution an original goal of the experiment (remember that this whole experiment started in 1988, long before the study in the present paper), (2) was favoring Cit+ evolution a purpose or one of the purposes of the glucose-cycling (giving the bacteria insufficient glucose supplies so as to cause alternating glucose feeding and starvation), and (3) what were other purposes -- if any -- of the glucose-cycling. Zachary Blount did not give a straight answer to the first question and gave no answers at all to the latter two questions. [[User:LarryFarma|LarryFarma]] 13:12, 29 June 2008 (EDT)
:::::::You continue to dwell on the semantics of 'goal' as though it has some particular relevance to the validity of the research presented in Lenski's latest paper. The experiment was started in '88 to track the evolution of a population of E. coli. The purpose of the 'glucose cycling' is to provide the bacteria with an environment that will favor those mutants that are better able to exploit a limited critical resource. The glucose cycling does not inherently favor the development of a Cit+ strain any more than it favors other potential solutions to the problem - like secreting a toxin to kill your competitors, or faster reproduction to outbreed them, or photosynthesis, or cannibalism, or what have you. There is no other purpose to providing the bacteria with a limited supply of glucose. Citrate is present in the growth medium as a chelating agent and buffer - it was not added solely to serve as a potential carbon source, although it is one.<br />
:::::::You seem to believe that the reason that Lenski is getting acclaim for this research is just that has isolated a strain of E. coli that can metabolize citrate under unusual conditions - and your response seems to be that he does not deserve praise for this, since he didn't set out with this particular outcome in mind - it's just an accident, if in fact the Cit+ bacteria exist at all. Or maybe you object because you think Lenski somehow 'stacked the deck' in favor of his bacteria becoming Cit+, so the results aren't 'fair' somehow. Or perhaps you think that after 20 years of failing to develop a Cit+ strain of E. coli through selection, Lenski just gave up, genetically engineered such a strain, and then faked his data. If you could clearly state what your suspicions are, rather than simply repeating that Blount won't answer your questions, it would be simpler to address your concerns.<br/>
:::::::This is utterly beside the point, however, because the importance of this recent paper does not depend on the detail of the strain being Cit+ - it could have been the development of a toxin, or some other event that led the new strain to be markedly, phenotypically different from its ancestors in some way. The importance lies in the work that was done to sketch out the outline of how the new trait developed, and in the re-development of the same trait during a re-running of the experiment from ancestral stock.<br />
:::::::Is it interesting that the trait seen in Lenski's E. coli is the metabolism of citrate under aerobic conditions? Yes. Is it remarkable? Yes, since you can count the number of E. coli strains that can do this on one hand. It's so wild and crazy that it might lead one to question whether the bacteria involved should even be called E. coli anymore - it's that striking a difference from 'normal' E. coli behavior. Was the development of the Cit+ strain an accident? Entirely. Would another Cit+ strain arise if the experiment was completely restarted from 1988? Almost certainly not - Lenski's data suggests that this is a staggeringly unlikely event, dependent on a series of merely overwhelmingly unlikely events. Did Lenski wish to develop a Cit+ strain from the beginning? No man can know the inner mind of another, but I would bet the farm that he didn't see this coming. If I were designing an E. coli breeding scheme with the stated purpose of selecting for a Cit+ mutant, I can think of much, much, much better ways to do it than this experimental protocol. The Cit+ trait is a novelty - an interesting one, one that is remarkable because of its rarity, one that resonates - but the value of the research does not depend upon it. --[[User:Brossa|Brossa]] 17:33, 29 June 2008 (EDT)
:::::::''"I'm sorry, I thought you were asking for help."'' You call that "help"? All you did was clutter up this talk page with your irrelevant "hypothesis" idea. With friends like you, who needs enemies? [[User:LarryFarma|LarryFarma]] 10:34, 29 June 2008 (EDT)
:::::::''"I'm sorry, I thought you were asking for help."'' You call that "help"? All you did was clutter up this talk page with your irrelevant "hypothesis" idea. With friends like you, who needs enemies? [[User:LarryFarma|LarryFarma]] 10:34, 29 June 2008 (EDT)
::::::::When did I call it help? I said that I thought you were asking for it. In any event Brossa seems to have clarified the situation.--[[User:British_cons|British_cons]] [[User_talk:British_cons|(talk)]] 11:38, 29 June 2008 (EDT)
::::::::When did I call it help? I said that I thought you were asking for it. In any event Brossa seems to have clarified the situation.--[[User:British_cons|British_cons]] [[User_talk:British_cons|(talk)]] 11:38, 29 June 2008 (EDT)