Dangerous bacterium hosts genetic remnant of life's distant past

Aug 12, 2010

Within a dangerous stomach bacterium, Yale University researchers have discovered an ancient but functioning genetic remnant from a time before DNA existed, they report in the August 13 issue of the journal Science.

To the surprise of researchers, this RNA complex seems to play a critical role in the ability of the organism to infect human cells, a job carried out almost exclusively by proteins produced from DNA's instruction manual.

"What these cells are doing is using ancient RNA technology to control modern gene expression," said Ron Breaker, the Henry Ford II Professor of Molecular, Cellular and Developmental Biology at Yale, investigator for the Howard Hughes Medical Institute and senior author of the study.

In old textbooks, RNA was viewed simply as the chemical intermediary between DNA's instruction manual and the creation of proteins. However, Breaker's lab has identified the existence and function of riboswitches, or RNA structures that have the ability to detect molecules and control gene expression - an ability once believed to be possessed solely by proteins. Breaker and many other scientists now believe the first forms of life depended upon such RNA machines, which would have had to find ways to interact and carry out many of the functions proteins do today.

The new paper describes the complex interactions of two small and two larger RNA molecules that together influence the function of a self-splicing ribozyme, a structure many biologists had believed had no role other than to reproduce itself. The new study, however, suggests that in the pathogenic stomach difficile, this RNA structure acts as a sort of sensor to help regulate the expression of genes, probably to help the bacterium manipulate .

"They were though to be molecular parasites, but it is clear they are being harnessed by cells to do some good for the organism," Breaker said.

This is the sort of RNA structure would have been needed for life exist before the evolution of double-stranded DNA, with its instruction book for proteins that carry out almost all of life's functions today. If proteins are necessary to carry out life's functions, scientists need to explain how life arise without DNA's recipe. The answer to the chicken or egg question is RNA machines such as the one identified in the new study, Breaker said.

"A lot of sophisticated RNA gadgetry has gone extinct but this study shows that RNA has more of the power needed to carry out complex biochemistry," Breaker said. "It makes the spontaneous emergence of life on earth much more palatable."

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User comments : 9

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ormondotvos
5 / 5 (1) Aug 12, 2010
Nice story, marred by egregious typos. Really, are chimps proofing these things?
Richak28
1 / 5 (1) Aug 12, 2010
Sounds as if Chimps are doing the original thinking ...
kevinrtrs
Aug 13, 2010
This comment has been removed by a moderator.
eldowan
5 / 5 (2) Aug 13, 2010
How could 'God' have created anything if everything obeys the same physical and chemical laws we observe on earth?

Unless there are areas in the observed / unobserved universe which do not obey such laws. But if that is the case, your argument falls apart.

Get over it. Already.
Skeptic_Heretic
5 / 5 (2) Aug 13, 2010
Get over it. Already.

Kev, technically you don't even believe in germ theory.

The evolution/creationism argument is over, you've lost.

Get over it.
Javinator
5 / 5 (2) Aug 13, 2010
You know kev... even if these is a God, you do realize that everything "He" does is done through chemical and physical processes dictated by the rules of our Universe (that God designed) right?

Since to you God created everything it means he also created all the scientific processes that make everything around us happen. Think about it. That's how "He" makes trees go and how "He" makes clouds form to cause rain.

Regardless of whether you believe things were all put here nicely by God or whether you don't, there's really no logical reason to be against studying and understanding the world around us and where we came from.
eldowan
not rated yet Aug 13, 2010
Jav,

I've never heard the argument you put forth, and I thank you for providing me a new perspective on the matter.
Ethelred
5 / 5 (1) Aug 14, 2010
That idea has been around for centuries. But some parts of it, as Javinator said it, are NOT accepted by many Christians.

you do realize that everything "He" does is done through chemical and physical processes dictated by the rules of our Universe


That part. It assumes no miracles and I don't think I have met a Christian that thinks that there have never been any of those. Indeed it requires that you deny the Resurrection.

Other than that it is a fairly reasonable statement of the thinking of many Semi-Rational Christians. Semi because Faith is, pretty much by definition, irrational.

Ethelred
Ethelred
5 / 5 (1) Aug 14, 2010
Life did not originate spontaneously anywhere in the universe - not if we assume the universe obeys the same physical and chemical laws that we observe on earth.
That radical assumption is based on solely your religious beliefs. There is no other reason to make such an assumption.
God created the universe; he also created life. Period.
And you know that how? What physical evidence supports your claim. I notice that you consistently refrain from actually backing your statement with evidence. All you have is an ancient book written by men even more ignorant than you. BUT they had an excuse. You are ignorant because learning about reality would spoil your religious beliefs.

More anti-ignorance to come
Ethelred
5 / 5 (1) Aug 14, 2010
The complexity observed in the cell is increasing [not decreasing] with each day of discovery that goes by
Not really. Early cells were much more simple. Not only that, we discovered that there are far fewer genes coding for proteins than anyone imagined, so the assumed complexity of life was found to be overstated by AT LEAST a factor of two and often more than four prior to the full mapping of human DNA.
Get over it. Already.
Why? You have NO evidence to support your beliefs. So why should we accept them?

Funny you NEVER want to answer that. Well maybe you WANT to answer but can't. Either way you don't answer it. Don't answer questions about the Flood either.

Ethelred