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Giardia Bares All: Parasite genes reveal long sexual history
Science News Online ^ | Jan. 29, 2005 | Christen Brownlee

Posted on 02/07/2005 1:15:22 PM PST by js1138

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To: Ichneumon

Unfortunately, my terseness is usually indicative of my impatience, and I'd be far more effective (and a bit less of a jerk sometimes) if I were a more patient debater. =)


121 posted on 02/07/2005 10:28:52 PM PST by AntiGuv (™)
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To: Southack
Your post #76 was exactly as I copied it, so there was no conditional unless it was implied by the ellipses..

I haven't read the entire thread so if you did qualify that statement in an earlier post then I apologize for my misunderstanding.

122 posted on 02/07/2005 10:32:26 PM PST by AntiGuv (™)
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To: AntiGuv
"Your post #76 was exactly as I copied it, so there was no conditional unless it was implied by the ellipses.. I haven't read the entire thread so if you did qualify that statement in an earlier post then I apologize for my misunderstanding."

It was perhaps easy to miss, but the IF was there (really, I promise)!

So...technically, an organism would be genetically superior if it had all of its functionality without also having unused genetic code as baggage. Natural Selection *should* favor those without the unused code...

76 posted on 02/07/2005 10:23:27 PM CST by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)

123 posted on 02/07/2005 10:36:16 PM PST by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Doctor Stochastic
I taught genetics over 40 years ago. There was no "one gene, one function" perception at that time. The mapping from "function" to "gene" was varied; sometimes one-to-one, sometimes many-to-one, sometimes one-to-many.

...and even "zero-to-one", as in the case of pseudogenes.

124 posted on 02/07/2005 10:37:21 PM PST by Ichneumon
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To: Southack
So shouldn't we see more junk DNA code in all older species?

What is an "older species?"

If all species descended from the same cell, all would be equally "old," in some sense. When a new species branches off from an old one, it does not do so in a pristine state, it carries over most of the mutations the last one had.

125 posted on 02/07/2005 10:54:17 PM PST by xm177e2 (Stalinists, Maoists, Ba'athists, Pacifists: Why are they always on the same side?)
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To: Southack
Ooooh, I see! You're not making an entirely absolute statement, but rather setting up a hypothetical scenario. Hmm.. Well, I do think now that we had some failure to communicate so I apologize for my part in that. OK, well lemme first say that I have a bit of a problem with the phrasing "genetically superior" as I already alluded. This might imply some kind of structural superiority and ultimately evolution is blind to that absent a functional manifestation.

So, the basic point is that as I said before: It's an open question which configuration, if either, would be favored by natural selection because it depends on the functional advantages of the difference. Natural selection would favor whichever one were most suited to whatever circumstances later arose, and would favor neither so long as there were no survival advantage between them.

If I actually had to venture a guess, I would guess that the G. intestinalis version with "junk" DNA would ultimately be favored, for the reason Ichneumon described:

Furthermore, in evolution "yesterday's junk" can become tomorrow's genetic innovation, as various bits of DNA get reshuffled, recombined, and mutated. There may be a short-term (and again, *tiny*) energy benefit in taking out the genetic trash, but keeping it around for future adaptive "spare parts" is probably well worth it in the long run.

But that can't be anything but conjectural on my part. It would depend on what circumstances the parasites were confronted with. Period. In their current niche, it'd almost certainly be a neutral distinction.

126 posted on 02/07/2005 10:55:21 PM PST by AntiGuv (™)
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To: xm177e2
"If all species descended from the same cell, all would be equally "old," in some sense. When a new species branches off from an old one, it does not do so in a pristine state, it carries over most of the mutations the last one had."

Besides the 4 unique "root" DNA lines, different branches of descent should have *some* different junk DNA, yes?! New species from a newer branch should have predictably different levels (given orders of magnitude) of junk DNA if Common Descent is actually in play, correct?

We wouldn't expect the levels to junk DNA to jump *both* up and down wildly if Evolutionary Theory was responsible, yes?!

127 posted on 02/07/2005 11:02:16 PM PST by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: betty boop

I missed your post among the fast and furious debate. I'm no expert. I know that the evolution of sex has been a source of debate, so it seemed likely that this finding is important. The experts are being cautious about what it means.


128 posted on 02/07/2005 11:28:51 PM PST by js1138
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To: Southack
different branches of descent should have *some* different junk DNA, yes?!

Yes, we would expect that.

Looking at the "junk DNA" in different species, we should be able to create a phylogenic tree that resembles phylogenic trees created on the basis of other measures of genetic similarity on and observed characteristics. These trees might not match up perfectly, that's okay, but they should be very, very similar.

New species from a newer branch should have predictably different levels (given orders of magnitude) of junk DNA if Common Descent is actually in play, correct?

I don't understand this. A "newer" species (one that branched off more recently) would still have most of the junk DNA from the older species. We might not expect it to have less new junk DNA than a species that branched off earlier, because their common ancestor would be accumulating junk DNA between the time both species branched off.

It's possible that junk DNA would accumulate more quickly during periods of rapid mutation/evolution, but I don't know if that's the case.

129 posted on 02/08/2005 12:18:06 AM PST by xm177e2 (Stalinists, Maoists, Ba'athists, Pacifists: Why are they always on the same side?)
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To: xm177e2
"I don't understand this. A "newer" species (one that branched off more recently) would still have most of the junk DNA from the older species."

That presumes that most junk DNA was accumulated prior to the branching off into newer species. Do we know that to be the case, or do species accumulate junk DNA on a more regular basis?

130 posted on 02/08/2005 1:14:27 AM PST by Southack (Media Bias means that Castro won't be punished for Cuban war crimes against Black Angolans in Africa)
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To: Ichneumon
Better to just keep it all and pay the negligble "rental price" on the useless portions than to risk "throwing out" something that actually *is* vital.

Reminds me of a science fiction story I read long ago, and I can't remember the title or author. It's the future, of course, and man has gone extinct -- as he so often does in these tales. What remains are androids which we had created. They reproduce and all that stuff, and they know all about man, and they have a cloning program to try to re-create man from old samples.

The androids had been careful to keep all the material and circuitry in their own bodies, and especially their brains, even though they couldn't understand all of it. They figured if man had put it there, it should stay. (And now you see what it was in your post that triggered this response.) Large sections of their brain circuits were a mystery to them, but they seemed harmless and non-functional.

Then they create a man. They had a woman too. (I don't recall why, but these humans were adults, and could speak. Maybe they had been frozen away somewhere.) One of the androids comes into the humans' room, and the man says: "Oh, here comes another one. What do you want?"

The old, mystery circuits in the android's brain click in. He bows his head, low, and responds: "I want only to serve you, master."

131 posted on 02/08/2005 3:06:24 AM PST by PatrickHenry (<-- Click on my name. The List-O-Links for evolution threads is at my freeper homepage.)
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To: jwalsh07; js1138; furball4paws; PatrickHenry
[Dembski writes:] "Far from saying that all 47 have to be precisely specified, I said, “…if only 6 of these 47 mutations were essential for the evolution, the probability of achieving it in 30 years is about 3 x 10^-35.”"

I'm just *dying* to see exactly how he calculated that alleged "probability"...

It's highly suspicious that Spetner just tossed the number out without even a hint of what sort of math he used.

And any number that freakin' low for "six mutations in 30 years" in bacteria (which mutate at the drop of a hat, and have mind-bogglingly large populations and reproductive rates) seems patently bogus on its face.

Jwalsh07, would you care to email Spetner and ask to see his calculations? I can't find a recent reference to an email address for Spetner (he doesn't even seem to have a homepage or a faculty page anywhere), but lspetner@alum.mit.edu worked as of several years ago (no clue if still does).

132 posted on 02/08/2005 4:26:18 AM PST by Ichneumon
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To: Southack
Evolutionary Theory completely and totally breaks down in the face of genetic code skipping. DNA that skips an entire intermediate species falsifies Evolution...and it can't be argued otherwise by even the most rogue-ish and obstinate of Darwinists.

Interesting. Please elaborate. I remember reading something about this a year or so ago, but I've looked and there's not much information available.

Thanks, MM

133 posted on 02/08/2005 7:01:09 AM PST by Michael_Michaelangelo (The best theory is not ipso facto a good theory. Lots of links on my homepage...)
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To: Ichneumon

"[Dembski writes:] "Far from saying that all 47 have to be precisely specified, I said, “…if only 6 of these 47 mutations were essential for the evolution, the probability of achieving it in 30 years is about 3 x 10^-35.”"

I'm just *dying* to see exactly how he calculated that alleged "probability"... "

Actually I mentioned this in an earlier post. If you assume a 10-6 mutation rate for most mutations (a reasonable guess in bacteria) and you posit 6 mutations occuring at the same time in one bug then you get 10-6x10-6x10-6x10-6x10-6x10-6 = 10-36 probability. Just shows you how people will twist stuff to make it fit their wishes.

Of course, it could take as little as 6 days to get those 6 mutations, one at a time.


134 posted on 02/08/2005 7:35:37 AM PST by furball4paws ("These are Microbes."... "You have crobes?" BC)
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To: furball4paws
The bugs that eat halogenated hydrocarbons are even more interesting!

You mean like PCB's?
Or fluorinert, the coolant in old Cray supercomputers?

Gives a whole new meaning to computer bugs, that does! /grin

135 posted on 02/08/2005 7:59:17 AM PST by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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To: xm177e2
So...technically, an organism would be genetically superior if it had all of its functionality without also having unused genetic code as baggage. Natural Selection *should* favor those without the unused code...

If the cost of keeping the code around is extremely low, then it probably won't get selected out any time soon.

Just like real code...there's always time to do it over, but there's never time to do it right in the first place!

136 posted on 02/08/2005 8:02:46 AM PST by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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To: grey_whiskers

You mean like PCB's?
Or fluorinert, the coolant in old Cray supercomputers?

Gives a whole new meaning to computer bugs, that does! /grin


PCB's you bet. Fluorinert is a new on for me. What's its chemical make up? (It's not in my Merck Index either).


137 posted on 02/08/2005 8:06:11 AM PST by furball4paws ("These are Microbes."... "You have crobes?" BC)
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To: furball4paws

'Twas a trade name for a fluoro- or chlorofluoro- carbon
which circulated within (say) the Cray-2 in direct contact with the circuit boards to dissipate heat.
I'll poke around my old files this evening or so and see
if I can find more for you.

PS Two questions.
a) what the hell do those PCB-eating bugs excrete?
b) I imagine metabolizing conjugated systems leads to
all kinds of free radical production; how do they
deal with it?
and a third:
c) Has anyone thought of getting "two for the price of
one" for the PCB-eating bugs and engineering further
enzymes so they excrete industrially useful
feedstock or intermediates?

Cheers!


138 posted on 02/08/2005 8:34:28 AM PST by grey_whiskers (The opinions are solely those of the author and are subject to change without notice.)
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To: furball4paws
The point is well taken that you cannot determine probability based on 6 mutations all occurring at one time in one bug. However, given that the average bacterial culture contains 1,000,000,000 bacteria per ml, a liter would have 1,000,000,000,000 bacteria. An average mutational rate of 1/1,000,000, means that there are 1,000,000 mutants in a liter of bacteria. Digest these numbers and you will see how easy it is to get to a nylon eating bug in a short period of time.

Wouldn't you have to account for the ratio of "favorable mutations" to all mutations? Any idea what that ratio is in bacteria?

139 posted on 02/08/2005 8:38:05 AM PST by jwalsh07
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To: Ichneumon
Jwalsh07, would you care to email Spetner and ask to see his calculations? I can't find a recent reference to an email address for Spetner (he doesn't even seem to have a homepage or a faculty page anywhere), but lspetner@alum.mit.edu worked as of several years ago (no clue if still does)

I would love to but I can't find him. More to the point, I think it more likely that he would answer a felow scientist rather than a blue collar small businessman. :-}

140 posted on 02/08/2005 8:41:43 AM PST by jwalsh07
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