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Author Topic:   Can Domestic Selection cause Macroevolution?
Rahvin
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Posts: 4032
Joined: 07-01-2005
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Message 152 of 157 (453733)
02-03-2008 10:06 PM
Reply to: Message 151 by randman
02-03-2008 8:43 PM


Re: not following you
Can you show me the study that compares neutral and beneficial mutational rates, heck even bad mutational rates, any peer-reviewed studies whatsoever addressing this most basic claim of evos?
I doubt you can. No one has ever been able to do so thus far. My guess is the studies weren't done and the assertions of evos just taken on faith to a degree.
There are many studies on mutation rates. Here's one for HIV:
quote:
Abstract:
The level of genetic variation of human immunodeficiency virus type 1 (HIV-1), a member of the lentivirus genus of the Retroviridae family, is high relative to that of retroviruses in some other genera. The high error rates of purified HIV-1 reverse transcriptase in cell-free systems suggest an explanation for this high genetic variation. To test whether the in vivo rate of mutation during reverse transcription of HIV-1 is as high as predicted by cell-free studies, and therefore higher than that rates of mutation of retroviruses in other genera, we developed an in vivo assay for detecting forward mutations in HIV-1, using the lacZ alpha peptide gene as a reporter for mutations. This system allows the rates and types of mutations that occur during a single cycle of replication to be studied. We found that the forward mutation rate for HIV-1 was 3.4 x 10(-5) mutations per bp per cycle. Base substitution mutations predominated; G-to-A transition mutations were the most common base substitution. The in vivo mutation rates for HIV-1 are three and seven times higher than those previously reported for two other retroviruses, spleen necrosis virus and bovine leukemia virus, respectively. In contrast, our calculated in vivo mutation rate for HIV-1 is about 20-fold lower than the error rate of purified HIV-1 reverse transcriptase, with the same target sequence. This finding indicates that HIV-1 reverse transcription in vivo is not as error prone as predicted from the fidelity of purified reverse transcriptase in cell-free studies. Our data suggest that the fidelity of purified HIV-1 reverse transcriptase may not accurately reflect the level of genetic variation in a natural infection.
"Beneficial" vs. "neutral" vs. "negative" are relative. A "neutral" mutation can turn out to be "beneficial" if a certain environmental pressure selects for it (or negative if an environmental pressure selects against it), but absent that environmental pressure, the mutation essentially does nothing meaningful. These are all subjective words defined by humanity - mutations themselves simply are, and do occur at a statistically predictable rate.
Take, for instance, an imaginary mutation in a bacterium that makes it resistant to a certain antibiotic, but more vulnerable to another type. In the absence of both antibiotics, it's a neutral mutation. One antibiotic or the other could make it a positive mutation or a negative one - it all depends on the environment. We can predict how often mutations will occur, but there are additional variables for "positive" vs "negative" vs "neutral," and they can even change during the lifetime of the organism. So your question is meaningless.
Edited by Rahvin, : spellign.

When you know you're going to wake up in three days, dying is not a sacrifice. It's a painful inconvenience.

This message is a reply to:
 Message 151 by randman, posted 02-03-2008 8:43 PM randman has not replied

  
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