Right!
Posted on 02/07/2005 1:15:22 PM PST by js1138
Right!
I agree. A more productive use of the time would be trying to find a quick cure for people infected with this bug. I've known some people who were infected with this organism. It's hard to shake off and your miserable while waitng for the drugs to have effect.
See post #67. It takes longer to diagnose than it does to treat it. :)
I suspect Southack may be referring to this:
http://nwcreation.net/articles/recombinationreview.html
"I know there is a mechanism called "back mutations" which can restore lost information such as your hypothetical gene 451. What I don't know is the rate at which such mutations occur. Any idea?"
It depends on what kind of mutation it was. A frame shift or base pair substitution could back mutate at frequencies as high as 10^-4 (more typically 10^-6 - 10^-7). If it's a deletion mutation, it ain't going to happen, ever, without the introduction of extra DNA from an outside source.
I can't think of any kind of mutation that "adds information to the genome". The only way I can see this happening is through genetic recombination (yes, bacteria have sex), via the mechanisms transduction, transformation and conjugation. You just can't stick a whole gene's worth of DNA into a cell without getting it from somewhere.
You are correct, but I've seen many hikers in the Sierras that have no clue about such things and they drink the water in lakes and streams.
A "favorable" mutation is one that increases the chances of having offspring. Unfavorable would mean that the chances of offspring were reduced. Neutral means that no tendence is introduced. These are all ex-post terms. Generally, one cannot give an ex-ante specification of which types of mutations fall into each catgory. A change in environment can change a mutation from favorable to unfavorable or vice versa.
Ding! Ding! Ding! We have a winner!
This "problem" is merely an artifact of your model. You seem to assume that the species you call B at present is the same as it was as the first branching point and that it must have lost gene 451 between the first and the second branching point.
However, the more likely scenario is the one where species B still has gene 451 after branching off from species A and only loses it after splitting off from species C.
This confusion could be avoided if you used different labels after each branching point, i.e.:
Species A branches into species B and C. Later, species C branches into species D and E.
Today we observe that species B and E both have gene 451 but not species D. This may be explained by the fact that species C lost the gene but somehow species E magically regained it or which is more likely, that species C still had gene 451, inherited it to both D and E but later D lost it. (Of course there is also the scenario where species A didn't have this gene and B and E 'evolved' it independently of each other, but this is even more unlikely)
For those creationoids who think there's a "gotcha" here, I suggest they think (and I mean "think") twice.
The apparent species skipping is just not so.
Your (BMCDA) post is quite good.
js1138 (?) also showed that the problem could well be associated with incorrect taxonomy, something that is always being updated and corrected. Science is not static.
The other possibility is that the gene is really not "missing", just cryptic or recessive or modifed (could even be post translation modification, or mutated simply so that it can revert to wildtype at a later stage.
All of these are much more probable and fit Occam's Razor much better that ID or some other mystical mush.
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