Evolution's “Molecular Clock”: Not So Dependable After All?

PLOS (Public Library of Science) ^ | 8/17/04 | Staff

[Michael_Michaelangelo]

So now we have the “punctuated equilibria” theory, which postulates that the fossil clock fluctuates wildly (long periods of stasis punctuated by rapid periods of evolution) and a wildly fluctuating molecular clock. Does anybody know what time it is? Course, problems with the molecular clocks *have* been reported before:

Erratic overdispersion of three molecular clocks: GPDH, SOD, and XDH

[delapaz]

Back to the old drawing board I guess...

[Michael_Michaelangelo]

Ping

[orionblamblam]

Science continues to self-correct with further information. Evolution remains the sole reasonable explanation of speciation, and is refined.

[Wonder Warthog]

"So now we have the “punctuated equilibria” theory, which postulates that the fossil clock fluctuates wildly (long periods of stasis punctuated by rapid periods of evolution) and a wildly fluctuating molecular clock."

These two hypotheses are NOT contradictory, and in fact tend to support one another. I would surmise that a variation in the "tick time" of the molecular/DNA clock is what controls "punctuated equilibrium".

My own take on the subject is that in times of increased stress, the rate of DNA change increases.

[Old Professer]

DNA mutates, and it's a good thing it does.

Don't disagree, you'll be banished to the cornfield. (Apologies to Rod Serling)

[ClearCase_guy]

I would surmise that a variation in the "tick time" of the molecular/DNA clock is what controls "punctuated equilibrium".

That's a good theory to have if you're interested in defending an existing theory which is apparently flawed.

On the other hand, if you want to look dispassionately at the evidence and engage in science based on that, then such "surmizing" seems contra-indicated.

[Michael_Michaelangelo]

Purposeful mutations good. Random mutations bad.

Researchers find clues about how antibodies specialize

From the article:

"The AID-RPA interaction must be regulated to bring about the specificity of the mutation," Chaudhuri says. "If this regulation is impaired for some reason, then the B cell would incur a lot of random mutations and that might lead to tumors."

[delapaz]

Is it unreasonable to believe in God?

[Socratic]

“U” always follows “Q” and “B” never follows “V.”

I guess this guy never went to a musical revue. (Some may claim the gay gene derived from just such a pairing).

[bondserv]

"Vowles and Amos estimate that as much as 30% of the genome may show evidence of convergent evolution, simply because microsatellites are so common."

So genes are converging 30% of the time, that wreaks havoc on the idea that there is enough time for the divergent species we see.

Mantra: Long ago and far away we had 99% divergent evolution, despite what we see today.

This also brings incite to the idea that married people begin to look more alike. (-|;|Þ "Americans are just a bunch of cowboys".

[Socratic]

“B” never follows “V.”

Can I just slink away in shame before the barrage starts? Please?

[glorgau]

In English,... “B” never follows “V.”

For techies who do programming, this is most certainly not true. :-)

[Malesherbes]

Well, we are told that these 30,000 genes are smart little buggers and mutate all over the place. We are never told how they got so smart. We are never told how it all began. God is implied if not acknowledged.

[Ichneumon]

So now we have the “punctuated equilibria” theory, which postulates that the fossil clock fluctuates wildly (long periods of stasis punctuated by rapid periods of evolution)

That's not what the article says, try again.

and a wildly fluctuating molecular clock.

That's not what it says either.

Does anybody know what time it is?

Yes, but you might need some assistance.

Course, problems with the molecular clocks *have* been reported before:

...and are well known. That doesn't make them useless, however, as you and other creationists often try to imply. Why don't you leave science to people who know something about it?

[Ichneumon]

Back to the old drawing board I guess...

No need.

[AndrewC]

Thus, if orangutans diverged from humans twice as long ago as did chimpanzees, on any given piece of DNA we would find twice as many differences between the orangutan sequence and the human sequence as between humans and chimps.

Thanks for the ping.

That statement is false, unless the "on any given piece of DNA" is changed to indicate DNA which would not be "adjusted".

[Wonder Warthog]

"On the other hand, if you want to look dispassionately at the evidence and engage in science based on that, then such "surmizing" seems contra-indicated."

I'm a scientist---I do that for a living. Based on thirty years of experience in science, I have yet to see any scientific evidence that contradicts evolution (and I include all the "evidence" that shows up on the evolution/creationism threads here).

DNA is a chemical system (I'm a chemist). Chemical systems are influenced by the environment in which they happen. Stress changes the chemical environment within living systems--therefore, the rate at which DNA changes SHOULD change. I have long felt that the idea of a "constant" molecular clock was not valid (based on chemical considerations). The best one can do is develop an AVERAGE rate of change of DNA change based on kinetic rates in systems we have evidence for today. I also expect that they will find (when enough evidence has been collected), that the "clock tick rate" will vary from one species to another.

[Ichneumon]

That's a good theory to have if you're interested in defending an existing theory which is apparently flawed.

It's only "apparently flawed" to creationists, because they frantically grasp onto articles like this and misunderstand them and their consequences.

On the other hand, if you want to look dispassionately at the evidence and engage in science based on that, then such "surmizing" seems contra-indicated.

...because...?

[Ichneumon]

Purposeful mutations good. Random mutations bad.

...and you've misunderstood/misrepresented *that* article, too.