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Author Topic:   Disabling Bacterial Resistance
RAZD
Member (Idle past 679 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 16 of 60 (216720)
06-13-2005 8:26 PM
Reply to: Message 1 by gnojek
05-24-2005 3:55 PM


Rate of Mutatability
One of the biggest problems I have with a lot of current genetic research is the fairly consistent assumption of constant (or relatively constant) rates of mutation as an environmental factor.

There are other experiments where the rate of mutation has been shown to encrease in response to stress, as if stress turns on a mutation switch.

We also know that some parts of the genome are much more susceptible to mutation than others -- that some mechanism is {protecting?} the sections with less mutations.

It could be something as simple as a coiling in the DNA that leaves some sections less {available/visible/exposed} than others, and stress causes an uncoiling.

We also know that environmental conditions have changed enough at different points in the past to have a significant effect on some of the environmental causes of mutation (production of 14C variation with climate is one {measure\example}).

It seems to me that the {rate of mutatability} has also evolved to ensure that not too much and not too little occurs in similar generations, that there is a {number of} mechanism{s} that can turn up or turn down susceptability to adapt -- after all, all the DNA that is around today is {highly?} evolved compared to ancestral DNA.

After all, a species that mutates too fast generates a lot of variation away from a known survivor and in it's extreme makes the creationist caricature hopeful monster with no siblings for mates, while a species that mutates too slowly doesn't adapt fast enough to survive.

Thus not only does Goldilocks find that the rate of mutation causing events is "just right" for adapting to changes over time, but the evolvability of Goldilocks has evolved to be "just right" for the current rate of mutation causing events.


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}


This message is a reply to:
 Message 1 by gnojek, posted 05-24-2005 3:55 PM gnojek has taken no action

Replies to this message:
 Message 18 by Wounded King, posted 06-14-2005 4:43 AM RAZD has replied

  
RAZD
Member (Idle past 679 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 60 of 60 (218131)
06-19-2005 9:05 PM
Reply to: Message 18 by Wounded King
06-14-2005 4:43 AM


Re: Rate of Mutatability
Where it gets to be a problem as I see it is when people then say that due to this assumed {relatively constant \ small sample averaged} rate of mutation that species {A} and {B} shared a common ancestor n.nnnnnn mya.

We also have the evidence now that humans evolved at a fast pace (more mutations fixed in the genome in the same time period) than chimps and gorillas, and I have to wonder how this fits into the genetic common ancestor clock calculations.

Just my thoughts. Sorry for the delay, I've been away.


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}


This message is a reply to:
 Message 18 by Wounded King, posted 06-14-2005 4:43 AM Wounded King has taken no action

  
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