Re: Bacteria Planned Mutations?
- From: Darwin123 <drosen0000@xxxxxxxxx>
- Date: Tue, 28 Jul 2009 13:44:07 -0400 (EDT)
On Jul 27, 1:29=A0pm, Tom Hendricks <tom-hendri...@xxxxxxx> wrote:
Quote from "Out of Control" K Kelly.I don't think you are saying it right. Maybe you should quote him
"(Barry) Hall found that his cultures of E. coli would produce needed
mutations at a rate about 100 million times greater than would be
statistically expected if they came by chance. Furthermore, when he
dissected the genes of these mutated bacteria by sequencing them, he
found mutations in no areas other than the one where there was
selection pressure.
directly. There were no mutations present except at a certain specific
site on the chromosome.
This means that the successful bugs did notI remember vaguely that this wasn't the interpretation. The
desperately throw off all kinds of mutations to find the one that
works; they pinpointed the one alteration that fit the bill.
interpretation was that the bacteria was throwing off all sorts of
mutations, but just at that site. The mechanism that speeded up random
mutations supposedly worked only on that part of the chromosome. Also,
the increased rate of mutation didn't respond to a generic "increase
in natural selection." The bacteria increased its mutation rate in
response to one particular threat.
Different sites on the chromosome are subject to different rates
of mutation. Your implicit assumption is that all sites on the
chromosome mutate at the same rate.
There are computer viruses built to "randomly mutate" a few lines
of program. This subroutine is what security software usually uses to
identify the virus. The think is that the virus only "mutates" those
few lines. If it randomly mutated other lines in the program, it would
destroy itself. The virus doesn't examine the secutity software and
then change the lines accordingly.
There is also a class of programs called "genetic algorithms"
which, among other things, use natural selection.
You also aren't considering the possibility that these other
mutations died without reproducing. The bacteria did increase the
mutation rate at that site on the chromosome. However, most of the
mutations may have died off.
However, the work does show that not all mutations are completely
random with respect to the function. The bacteria has obviously been
programmed by evolution to change the mutation rate at a certain site
on the chromosme in response to a certain stimulus. However, this is a
still response to a stimulus that the bacterias ancestors have already
met.
Technically, evolution has been speeded up. However, what would
be consdered a "new innovation" can't be generated this way. Instead,
the bacteria has "chosen" to install an "old" version of itself. Its
like your new word processor isn't compatible with the XP operating
system, so you reinstall the Windows 2000 program that you saved on
some old CDs. There is no way you can change your operating system to
Apple, because your computer was never compatible with Apple. You
don't have Apple software saved on any CD's because your computer was
never compatible with Apple computers. The bacteria can't mutate into
anything really new, it can only make mutations in a certain area on
the chromosome reserved for a certain type of change.
.
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