argystokes
Posts: 766
Joined: Jan. 2006
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| Quote | Argy ...
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You wanted a real-world example of a reversion mutation, which must represent a gain of biological information if the original mutation represents a subtraction. I gave one to you. |
Sorry, but I did not see an example of a reverse mutation in that link. Could you post the exact snippet that you think contains this? |
| Quote | | In the test several strains of Salmonella typhimurium that carry mutations in genes involved in histidine synthesis are used. The bacteria require histidine for growth. The variable being tested is the mutagen's ability to cause a reversion to growth on a histidine-free medium. The tester strains are specially constructed to have both frameshift and point mutations in the genes required to synthesize histidine, which allows for the detection of mutagens acting via different mechanisms. Some compounds are quite specific, causing reversions in just one or two strains. [1] The tester strains also carry mutations in the genes responsible for lipopolysaccharide synthesis, making the cell wall of the bacteria more permeable, [2] and in the excision repair system to make the test more sensitive. [3] Rat liver extract is added to simulate the effect of the metabolism, as some compounds, like benzopyrene, are not mutagenic themselves but their metabolic products are.[4] |
And if you want specific examples of successful Ames tests, you could always click the links to the PDFs at the bottom of the wiki page. Or google.
So, Dave. Do these mutations represent a decrease in information? What about the mutations that made it so the bacteria couldn't synthesize histidine?
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"Why waste time learning, when ignorance is instantaneous?" -Calvin
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