Have we been here before? Or are we an experiment

The oldest rocks which have been found so far (on the Earth) date to about 3.8 to 3.9 billion years ago (by several radiometric dating methods). Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years. Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.

New Haven, Conn. -- Yale scientists report they have synthesized molecules like those that probably gave rise to the earliest life forms on Earth nearly 4 billion years ago, thus creating a biochemist's version of "Jurassic Park" populated by exotic molecular "fossils" that have long since become extinct.

In the May 26 issue of the Proceedings of the National Academy of Sciences, the Yale biologists report the creation of one of these "fossils," an unusual hybrid molecule made up of a scaffold from deoxyribonucleic acid (DNA) with chemical "scissors" attached to it.

Ronald R. Breaker, who created the first DNA enzymes in 1994 with colleagues at The Scripps Research Institute, said he "looted the tool box of proteins" to get the amino acid "scissors," which destroy messenger ribonucleic acid (RNA) in humans and many other organisms. The feat was accomplished using a technique known as test-tube evolution.

Breaker's tailor-made enzyme is the first known nucleic acid enzyme that uses an amino acid to trigger chemical activity, and it brings scientists a step closer to finding the precursor of all life -- a single molecule containing both genetic code and an enzyme capable of triggering self-replication.

"If we can raid a protein's tool box to take one of its favored chemical groups -- in this case, a key amino acid called histidine found in a protein called RNase A -- then we should be able to raid the entire tool box and make use of anything we find there to make highly sophisticated DNA or RNA enzymes," said Breaker, who collaborated with Yale postdoctoral associate Adam Roth.

Which Came First -- DNA, RNA Or Proteins?

The discovery provides important clues to the chicken-or-egg dilemma of which came first -- DNA, RNA or proteins. Most scientists agree life as we know it cannot exist without DNA as the storehouse of genetic code, RNA as the genetic messenger, and proteins to carry out the chemistry of reproduction. Can any one of these three key molecules have existed as the precursor of the other two, serving as both chicken and egg?

Evidence is mounting that "it was an RNA World at the dawn of life as the Earth began to cool," said Breaker, who added that he and his colleagues can create dual-purpose genetic enzymes in the laboratory out of either RNA or DNA. "These genetic enzymes have the chemical sophistication, the full catalytic ability, to do many of the fundamental reactions we see in biology today. I am confident one will be created soon that can replicate itself."

He added that the new DNA enzyme he crafted destroys RNA with impressive efficiency at a rate 10 million times faster than it would decay naturally, although the protein the enzyme mimics acts much faster still.

No naturally occurring DNA enzymes have been found to date, but such a discovery would not surprise Breaker. The discovery nearly two decades ago of naturally occurring RNA enzymes, or ribozymes, earned Yale biochemist Sidney Altman and University of Colorado researcher Thomas Cech the 1989 Nobel Prize in Chemistry. In separate experiments, Altman and Cech exploded the myth that RNA is merely a passive carrier of genetic code incapable of triggering cell activity.

Referring to the dozen or more DNA and RNA enzymes created in his laboratory in recent months, Breaker said, "We believe these are like ancient molecular 'fossils' that might have been found stomping around the planet -- or more likely floating in the seas -- during the Archean Era between 3.8 and 4 billion years ago."

RNA Identified As Strongest Candidate For Precursor To All Life

While the Yale biologists created the versatile protein mimic from DNA, Breaker theorizes that a similar enzyme could be created with RNA, which many scientists believe is the strongest candidate for being the precursor of all other life forms. In addition to RNA's dual function as genetic molecule and as enzyme, RNA serves important roles in all living systems as the carrier of genetic instructions from DNA and as the orchestrator of all protein synthesis.

"This is exactly what you would expect if RNA invented these processes during the 'RNA World,'" Breaker said. "Because DNA is about a million times more stable than RNA, DNA most likely evolved later as a safe storehouse for the genetic code first found in RNA. Similarly, proteins probably evolved that were more efficient chemical catalysts, eventually driving most RNA enzymes extinct and relegating RNA to a more limited role."

The discovery that nucleic acids can raid the tool box of proteins means "the RNA World could have been a very sophisticated place," Breaker said. "The earliest RNA could have had access to all of these chemical helpers now used by proteins. Instead of working from a very primitive palette, varieties of RNA could have evolved that had a very rich chemical capability early on."

Now if the earth has been around for billions of years do you think it is possible that We might be getting a second chance and that maybe we have evolved more than once?

Is it possible that at the begining of the planets birth Aliens could have introduced RNA or DNA to kick start life?

Are we a mixture of ET life? We could be the bastard sons of the universe

If you take all the probabilities and the even include planet X in this life would not be on this planet as it would get disturbed every 3-4K years

Maybe we are meant to be

I would like to discuss your views and opinions on the begining and what you all think...

A cool experiment for me would be if nasa dropped some dna on venus and see what happens

I didnt realise this has been delved into in another thread

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posted on 24-3-2008 @ 09:44 PM single this post "quote"REPLY TO:
Civilization was destroyed at least once before

It could have happened any number of ways, nuclear destruction, a great flood, meteorite impact, it doesnt matter. Another great civilization once populated this planet many thousands of years ago and in this thread i will attempt to explain how and why.

For starters it is ignorant to assume that if another civilization once thrived, that it us who built it. There could have been another type of humanoid race on this planet that thrived that was at the time superior to us. Or perhaps we were more advanced at an earlier time. The bottom line is once of the oldest skeletons of a modern day type human that was found is in and around 9000 years old. Either way the strange thing about humans is that our physical appearance and brain size and finction have been the same for tens of thousands of years yet, it has only been in the last few thousand years that we are intelligent enough to advance scientifically and socially? I don't buy that, we have been capable of doing all the things we do now for many thousands of years. Why only now?

The biggest thing we have to understand when trying to discover past histories is that if a great civilization was destroyed, such as ours, there would be little to no evidence that it ever existed 10000 years later. One must understand what happens to a society such as ours when we arent around anymore to maintain it. It is thought that if our population were to suddenly drop to as low as 100 million worldwide, that within just 300 years everything we have built would be around 80% eliminated through natural processes. This doesnt include destruction through war, or perhaps a meteor or flood. In fact such an event would probably accelerate it.

This is explained in great detail here channel.nationalgeographic.com...

After maybe a thousand years society would start to flourish again but the problem is we would once again face religious differences, racial divides, territory disputes, we would basically have to start over from scratch and things would be like they were a couple of thousand years ago.
You would wonder though, wouldnt the survivors of our civilization carry on our history and try to preserve technology? The answer is no. They would try but you have to remember survival is a full time job. They would be too busy tending crops, fighting off bandits and gangs, maintaining their crude structures and trying not to get killed by nature and disease to be able to teach modern knowledge, and preserve technologies. Eventually the generation that has the knowledge from the previous society will die off and so will the knowledge die with them. The newer generation will just have stories and fragments of teachings of the old ways. Each generation will lose more and more of this and education will slowly get weaker as the need to revert back to more primitive methods i order to survive will take priority. Also the means of producing technology will deplete and so will the knowledge of doing so.

YOu will see new religions rise up that nowwhere resemble the ones we have today. Mythologies will be based on our previous society. Leaders of large countries in our day will be spoken of asif they were gods or perhaps heros or even possibly as the destroyers. It would be interesting to see what people would interperet things such as Mt Rushmore or the base of the Statue of Liberty. The pyramids might still even exist.

The problem is once the new society becomes interested in finding out the past nobody alive has any direct knowledge of the previous society, nobody has any proof, and all they have to go on are stories that have been handed down for thousands of years and the stories have lost their origional meaning. Stories will be changed over time due to the method of record keeping (mostly orally recorded), the level of comprehension of the persons receiving the information and the amount of words in the vocabulary of the people retelling the story. In ancient times there were no words for automobile so instead a word such as chariot would have sufficed.

A flood would have completely destroyed most evidence from the get go. Vast cities would be covered under mud. Wet structures would rot and corrode much faster after the flood. Continents would be drastically altered as coastlines would be reshaped and new lakes and seas would be created. Nothing would be the same and all would be lost. Then add 10000 years to that and what would you get? Nothing at all. But there is no evidence of a flood you say? How isnt there? Every society on the planet has an ancient flood story.

You also hear of places like atlantis. Ive often wondered why we cant find atlantis. Perhaps it was not just a city but maybe it was what Earth was called before. Or maybe it is what Mars used to be called before it was destroyed. I think when we are searching for Atlantis we arent thinking outside the box yet on this one. Yes i do believe Mars had life at one point. There are theories that suggest it could have supported life as little as 12000 years ago if in fact have supported life.

Anways i will go into detail further on any one of these subjects as they come up. I would like to hear what you all think. Was there a past civilization? I would like to think so.

Not being a scientist, I find it hard to follow the terminology a bit, but from what I do get of what you are saying, it is distinctly possible that these RNA and/or proteins could have led to the formation of the DNA that we are all now aware of. It would go a long way to not only show how life origionally developed here on Earth, but how, over time, it branched out, first, from the single cell lifeforms which first inhabited the Earth to the most complex lifeforms which have ever existed on this planet, including humans. And many different species could have evolved, not from each other, but from many different RNA and/or proteins that in turn developed into DNA. So humans didn't necessarily have to develop from chimp/monkey DNA, even though the two species are real close as far as DNA structure goes. Maybe you can correct me if I am wrong, but that seems to me to be what you are saying.