Posted on 01/10/2004 8:05:30 AM PST by PatrickHenry
GAINESVILLE, Fla. --- Researchers at the University of Florida say they have shown that minerals were key to some of the initial processes that formed life on Earth. Specifically, a borax-containing mineral known as colemanite helps convert organic molecules found in interstellar dust clouds into a sugar, known as ribose, central to the genetic material called RNA. This announcement provides a key step toward solving the 3-billion-year-old mystery of how life on Earth began. The findings will appear in Friday's issue of the journal Science. Steven Benner, Alonso Ricardo, Matthew Carrigan and Alison Olcott built on a famous experiment done 50 years earlier by Stanley Miller that is found in many textbooks. In 1953, Miller showed that electric sparks in a primitive atmosphere made amino acids, the building blocks of proteins.
Miller's experiment failed to identify sugars that were needed for genetic material, however. "The sugar ribose can be formed from interstellar precursors under prebiotic conditions," said Benner, who led the research funded by NASA, the National Science Foundation and The Agouron Institute in Pasadena, Calif. "But ribose is too unstable to survive under Miller's conditions." Ribose, like most sugars, turns into tar if not handled carefully. "It is like baking a cake too long," said Benner, a UF distinguished professor of chemistry and anatomy and cell biology. In 1995, Miller gave up trying to make ribose prebiotically, writing: "The first genetic material could not have contained ribose or other sugars because of their instability."
Benner, who also is a member of NASA's Astrobiology Institute, did the first experiments as an instructor at an international geobiology course last summer funded by the Agouron Institute and held at the University of Southern California Wrigley Institute for Environmental Studies. "We asked two questions. First, what simple organic molecules might have been present on early Earth as starting materials to form ribose? Then, what might have been present on early Earth to capture ribose and keep it from burning up like overcooked cake?" Benner said.
To identify simple organic molecules that might be the starting materials, Benner turned to compounds known to exist in interstellar dust, such as formaldehyde, used to preserve tissue. "Formaldehyde may not seem to be a good starting point for the life that we know," he said. "But it is simple. With only one carbon atom, one oxygen atom and two hydrogen atoms, there is a lot of formaldehyde to work with in the cosmos."
Benner and his team showed that formaldehyde, with other interstellar compounds, could form ribose and other sugars when treated in the presence of base materials such as lime, a material used to adjust the pH level of lawns, among other things. Lime was effective, but the ribose decomposed soon after it was formed.
Recognizing that ribose had a particular chemical structure that allowed it to bind to minerals containing the element boron, they turned to another substance called colemanite. "Colemanite is a mineral containing borate found in Death Valley," he said. "Without it, ribose turns into a brown tar. With it, ribose and other sugars emerge as clean products." Benner then showed similar reactions with other borate minerals, including ulexite and kernite, which is more commonly known as borax.
Benner and his team are the first researchers to succeed in making significant amounts of ribose under these early conditions.
Joseph Piccirilli, a biological chemist at the Howard Hughes Medical Institute and the University of Chicago, said Benner's work "has simplicity and brilliance."
"Organic chemists have long known that borate complexes with compounds like ribose," Piccirilli said, "and prebiotic scientists have long believed that minerals on the early Earth played an important role in the origin of life." Until now, "no one has put the two ideas together," he said.
"We are not claiming that this is how life started," Benner stressed. "We are saying that we have demonstrated a recipe to make a key part of life without any biochemical machinery. The more recipes of this type that can be found, the more clues we have about how life could have actually gotten started on the primitive Earth."
While best classified as basic science, the work has practical biological and medical value. "Curiously, thinking about how life originated and what form it might take on other planets helps us design new tools for disease diagnostics and therapy," Benner said. Diagnostic tools enabled by Benner's work seeking alternative life forms are used today in the clinic to monitor the load of the viruses that cause AIDS and hepatitis C.
The work also complements other research Benner is conducting that focuses on ancient forms of life on Earth. In a September report in Nature, Benner and his collaborators deduced the structure of a protein found in a bacterium that lived several billion years ago and resurrected the ancient protein. By studying it in the laboratory, the group inferred the ancient bacteria lived in a hot spring at about 150 degrees Fahrenheit.
With the prebiotic experiments, Benner said, "we are working forward in time, from the origin of the planet to the first life. With experiments with ancient proteins, we work backwards in time, from the modern world to the most primitive of bacteria." The group's goal, he said, is to have the two meet in the middle.
Yes, but aren't most mutation's negative? Look at the number of genetic diseases in humans. Now look at the number of postive mutations in humans that we have identified.
It seems to me that the overwhelming majority of mutations are negative. Many of those will be culled from the gene pool before they can reproduce. But not all of them. Many of the negative mutations will reproduce. Repeat...repeat again....repeat again.
Negative mutations are spreading through the gene pool. Without significant environmental pressure, it seems like the natural course for any species would be to decline over time.
Thus I'm formulating a new principle, that says any species that becomes dominant shall begin to degrade in the absence of sufficient survival pressure. Let's see I need a name for this principle. "The Peter Principle" - no been used already for something similar. "The Principle of Natural Degradation of Dominant Lifeforms" - too long. "De-Evolution" - No, coined before me and is bigger in scope than this principle.
"Dominance Paradox" - Hey I kind of like that. Any lifeform that becomes dominant enough that minor negative mutations are not immediately culled out of the gene pool will begin to degrade. Discovered here today by DannyTN.
Let the Pee-er mocking of new ideas begin!
Some are. Some aren't. Here's a thread from two days ago Ice Age Ancestry May Keep Body Warmer and Healthier which discusses favorable mutations. I don't know why you imagine mutations must be unfavorable. A mutation might make you smaller, or maybe taller; weaker or maybe stronger; allergic, or maybe resistant to an irritant, etc.
Besides, death takes care of the truly unfavorable mutations, and the rest -- however few they may be -- go on to breed the next generation. Evolution keeps increasing its bets on the individuals that survive. Every species now living is a consequence, and those species are but a tiny fraction of all the species that once lived. Each of us is a long shot, but here we are. That's evolution.
I don't think they "must" be unfavorable. I just think the overwhelming majority are.
After all it's much easier to modify the genetic code to delete an organ or diminish it's functionality, than , than it is to add a new organ or add new functionality to an exising organ.
Death does take care of severe mutations and mating preferences others. But it still seems like for every positive mutation there would be Thousands and probably millions of mutations that diminish functionality in some respect.
Thus evolution processes to be considered credible must not only find be able to adding significant functionality in relatively short time-frames, but must overcome the deteriorating effects of most mutations being negative.
Evolution is most definitely considered credible -- to those who have made a study of the subject. You might take a look at this: mutations create new variation, which I found quickly, and it only hints at the information which is available on this subject.
Coming to this subject new, as you apparently are, it's easy to be unaware that all of your objections have been dealt with for generations. If your only source of information is what you glean from hanging out at creationist websites, then you are cheating yourself. Anyway, if you are interested in the subject, you ought to study it systematically. You would be amazed at how exposure to already-existing information will change your views.
I'm moving on now. Please, don't imagine it's because your objections to evolution have overwhelmed me and that you have thrown 150 years of biology into a tizzy. I just don't have the time for this thread right now. It's been good chatting with you.
That article is faulty in assuming that there was not the potential for variation in the orignial bacteria. Until scientists fully understand all of the bacteria's code and how it functions, they cannot claim that variation only comes from mutation and was not already inherent in the code in the one bacteria.
It's not sufficient to say they all came from one chromosome, because until you understand the functionality of recessive genes and all DNA (previously called junk DNA) you can't claim that the variation is exclusively mutations.
Nevertheless, I'm not saying variations don't arise from mutations, just that most of those are negative.
But I agree let's move on.
How many mutations have you counted? And how did you judge them to be positive or negative?
Isn't this a 4.55-billion-year-old mystery???
It's not a fallacy to say the evidence makes the current evolution theory "incredible" or "unbelievable". That there must be something other causative agent.
Who was that man?
I'd like to shake his hand
He made my baby
Fall in love with me
It is hardly a reflex, unless you mean a gag-reflex. If you are going to take a creationist stance and make caustic remarks about the probity of current biological science, don't be unduly surprises if your alternative explanation comes under fire.
The communists in America invested lots of time conditioning academics to immediately point to a murderous, hypocritical church when the need or opportunity presented itself in any scientific discussion.
Yes indeed, american academics have been mindlessly trained, like Pavlov's dogs, to drool on command. During their hypnotic communist training sessions. One can easily tell by all the denegrating references to the church in "Nature" and "Science".
I'm not singling you out or anything; we're all dripping with vestigal socialist associations. One needs to know where one is comming from so hopefully the "scientific" and "religious" dialectic does not degenerate into a socio-political squabble.
Now that you've got your insulting zingers in, and want to return to emulating an adult, One hopes that the subject of borax minerals and life might be returned to.
And which, if the diminishment is significant, therefore get eliminated from the gene pool. It is not significant that "useless" mutations outnumber "useful" mutations if the screening process only favors the useful mutations--which it obviously does. Most mutations, by the way, are neutral; a few altered molecules in the DNA chain will usually not effect the functionality of most proteins. So creatures carry around various forms of DNA patterns for the same functions. These sometimes get embodied as recessive and dominant traits, and hang around for millenia waiting for the right environment to favor them. The picture you are trying to work with to suggest the potency of bad genes over good genes has been simplified to the point of dis-utility. DNA is far more accomodating of useful variation than you imagine it to be.
Darwin addressed that by saying that society was fatal to to his theory due to what he termed "misplaced compassion," he actually was forecasting a sort of evolutionary confusion where no real progress could occur.
I believe it was his cousin who came up with the notion of social evolution as a means of explaining class structure, but society stood ready to do battle with that then as well as now; so we wait.
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