New TSRI study offers surprising twist on how life began on Earth

TSRI Scientists Find Evidence for Alternate Theory of How Life Arose

A new study led by scientists at The Scripps Research Institute (TSRI) offers a twist on a popular theory for how life on Earth began about four billion years ago.

Ram Krishnamurthy is an associate professor of chemistry at The Scripps Research Institute.

The study questions the “RNA world” hypothesis, a theory for how RNA molecules evolved to create proteins and DNA. Instead, the new research offers evidence for a world where RNA and DNA evolved simultaneously.

“Even if you believe in a RNA-only world, you have to believe in something that existed with RNA to help it move forward,” said Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI and senior author of the new study. “Why not think of RNA and DNA rising together, rather than trying to convert RNA to DNA by means of some fantastic chemistry at a prebiotic stage?”

The study was published recently in the journal Angewandte Chemie.

A Look Back in Time

Researchers have explored the RNA world hypothesis for more than 30 years. The idea behind this theory is that a series of chemical reactions led to the formation of self-replicating RNA molecules. RNA then evolved to create proteins and enzymes that resembled early versions of what makes up life today. Eventually, these enzymes helped RNA produce DNA, which led to complex organisms.

On the surface, RNA and DNA molecules look similar, with DNA forming a ladder-like structure (with nucleobase pairs as the rungs and sugar molecule backbones as the sides) and RNA forming what looks like just one side of a ladder.

If the RNA world theory is accurate, some researchers believe there would have been many cases where RNA nucleotides were mixed with DNA backbones, creating “heterogeneous” strands. If stable, these blended “chimeras” would have been an intermediate step in the transition to DNA.

Problems with Instability

However, the new study shows a significant loss of stability when RNA and DNA share the same backbone. The chimeras do not stay together as well as pure RNA or pure DNA, which would compromise their ability to hold genetic information and replicate.

“We were surprised to see a very deep drop in what we would call the ‘thermal stability,’” said Krishnamurthy, who in addition to his position at TSRI has joint appointments with the National Science Foundation (NSF)-National Aeronautics and Space Administration (NASA) Center for Chemical Evolution and the Simons Collaboration on the Origins of Life. This instability appeared to be due to a difference in the DNA sugar molecule structure versus the RNA sugar molecule.

The finding supported previous research from Nobel laureate and Harvard University Chemistry and Chemical Biology Professor Jack Szostak that showed a loss of (nucleotide-binding aptamer) function when RNA mixed with DNA.

Because of this instability, chimeras in the RNA world would have likely died off in favor of more stable RNA molecules. This reflects what scientists see in cells today: If RNA nucleobases mistakenly join a DNA strand, sophisticated enzymes will rush to fix the mistake. Evolution has led to a system that favors more stable, “homogeneous” molecules.

These sophisticated enzymes were probably not around at the time of RNA and DNA’s early evolution, so these substitutions may have had a crippling effect on the molecules’ ability to replicate and function. “The transition from RNA to DNA would not have been easy without mechanisms to keep them separate,” said Krishnamurthy.

Considering a Second Theory

This realization led the scientists to consider an alternate theory: RNA and DNA may have arisen in tandem.

Krishnamurthy emphasized that his lab is not the first to propose this theory, but the findings on chimeric instability give scientists new evidence to consider.

If the two evolved at the same time, DNA could have established its own homogeneous system early on. RNA could have still evolved to produce DNA, but that may have occurred after it first met DNA and got to know its raw materials.

Krishnamurthy added that scientists will never know exactly how life began (barring the invention of a time machine), but by considering circumstances of early evolution, scientists can gain insights into the fundamentals of biology.

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Comments

  1. Gordon L. Scott Gordon L. Scott United States says:

    But the key here is that somehow, random molecules assembled themselves into self replicating engines, not just once but perhaps millions of times before making a sustainable life form.  The odds against such events are more than astronomical, they are completely beyond belief!  Face it dudes, life began on earth as a result of intelligent design.  I know that doesn't fit with your atheism, but that is the ONLY reasonable explanation.

  2. Calven McVetty Calven McVetty United States says:

    "The finding supported previous research from Nobel laureate and Harvard University Chemistry and Chemical Biology Professor Jack Szostak that showed a loss of (nucleotide-binding aptamer) function when RNA mixed with DNA."  
    Kinda says it all right there.

  3. Joe Clinton Joe Clinton United States says:

    Believers already know how life came to be..a great entity just willed it and presto!..there was life on earth.

  4. Jackie Winters Jackie Winters United States says:

    Ram Krishnamurthy  may I give you some knowledge of where to find that true information about how man got started I will give you some direction.
    Yes it was God the creator of all things who made that things you think is the beginning, you can't jump to one thing made away from how did it get here in the first place, as in who created it.  
    If you really want to know how man got started read the Book of Genesis the Holy Bible written by the inspiration of God the Creator of all things including you.
    If you want to think you came from some sore of something, ask yourself, How did this thing come to be and if you find that thing ask yourself how did this thing come to be.
    God made all things and he has been here since before time began.

  5. Cleve Watson Cleve Watson United States says:

    "New TSRI study offers surprising twist on how life began on Earth"

    MAY have begun ... there are a LOT of assumptions about this topic, none of which can be proven in any way.

  6. Paul Sell Paul Sell United States says:

    The best theory of Evolution is the "Fecal Deposit" theory. Eons ago a couple of space travelers were cruising the Universe looking for adventure. Passing Earth, one remarked after a scan, "That atmosphere is habitable to us. Let's take a look." They landed their craft and after a picnic on a nice beach one said he had to poop. He went to a rock outcropping and relieved himself and they both left. Later that afternoon the tide came in and washed his poop out to sea. The warm sea water caused the bacteria in his poop to start to grow and multiply forming at first one celled animals. And that my friends is as good as any Evolutionist can get. Me? I think it is a bunch of sh!t....

  7. Gary Rose Gary Rose United States says:

    Cut the crap, we were put here by aliens millions of years ago.

  8. Vladimir Shalamov Vladimir Shalamov Russia says:

    Moronity TSRI and NASA has no limits. DNA has not evolved. DNA was created and was converted by revolutionary way.

  9. Homey Slice Homey Slice United States says:

    6000 years ago man created man! In his image! Done end of story.

  10. J Kevin Doyle J Kevin Doyle United States says:

    DONT YOU JUST LOVE IT WHEN CRAP LIKE THIS IS POSTED AS TRUE AND IT IS FILLED WITH THEROY AN COULD BE AN MAY BE WHO CREATED ALL THE ELEMENTS BEHIND IT AT THE VERY BEGINNING ? JUST MAKEING YOUR LIFE SIMPLE GOD CREATED EVERYTHING PERIOD STOP DOING SATINS WORK IT WONT FLY

  11. Jonathan Cohen Jonathan Cohen United States says:

    This article lost me the minute i read believe .,..
    “Even if you believe in a RNA-only world, you have to believe in something that existed with RNA to help it move forward,” said Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI and senior author of the new study.

    Sadly the use of the word believe/belief in any scientific article loses its currency.  Science is not based on any belief, it strictly based on observable facts that supports a hypothesis.  Science needs to remove the word "believe/belief" from its vernacular!!! This is why the religious fanatics point to science as a region WHICH IT IS NOT!!

  12. Twice Born Twice Born United States says:

    Animal life began when God (JESUS) spoke it into existence.  Human life began when God (JESUS) breathed into man the breath of life.  Any other explanation is foolishness.

  13. Louis Marsten Louis Marsten United States says:

    The truth is that we were all "space travelers" floating through "inner space" for nine months, and then expelled into an environment where absolutely Nothing was recognizable! The arrogance on display throughout history by some of us "humans" is truly astonishing! The answer is that "origin" questions are unknowable and those "guess and by golly" speculations border on silliness! What we call God and when we state that we ourselves are created in the "Image of God, all we really know as truth is that , looks aside, Only "God" can "exnihilate", that is toe create something from nothing, so where we share in that image, we have a similar ability to create, but can only create something from or out of something else!

  14. Michael Copeland Michael Copeland United States says:

    Well....I'm impressed.  Back to a second a coffee....

  15. Andy Long Andy Long United States says:

    DOI number please?

  16. al wash al wash United States says:

    Genesis 1:1, "In the beginning, GOD created the Heavens and the Earth."  So, "consider" all you want.  Impress me by "re-creating"  everything.  I'll give you the "Big Bang", but you have to tell me exactly, who, created the bang.  God bless

  17. Prabhash Dubey Prabhash Dubey United States says:

    The Entire creation process is explained in the Vedas so why does the world just follow this scripture - http://www.vedabase.com/en/sb

  18. Clem C Clem C United States says:

    They used to tell us that the "primordial chemical soup" was energized into life by cosmic radiation and/or lightning storms.  I guess that one went out the window, too.

  19. BEN CALVERT BEN CALVERT United States says:

    Another scientific theory. I guess they have all the facts also. But which one to choose from. I vote none of them.

  20. Delampady S. Bhat Delampady S. Bhat United States says:

    Amazing study, and outstanding results.

  21. Werner Olivier Werner Olivier Australia says:

    So many scientists are so blinded by their refusal of the possibility that God created the world that they do not see how ridiculous their theories are.
    So, RNA couldn't have converted into DNA, so they had to have started evolving together. The whole point behind the original RNA to DNA theory was that RNA is less complicated and therefore more plausible to have spontaneously self-assembled. Now we are told that even the more complicated DNA came together automatically.
    To quote the professor: “Why not think of RNA and DNA rising together, rather than trying to convert RNA to DNA by means of some fantastic chemistry at a prebiotic stage?”
    Yet we are to believe that DNA and RNA could spontaneously self-assemble by some fantastic chemistry.
    I'm sorry, but biogenesis is simply impractical and using probability completely impossible.

  22. James Cline James Cline United States says:

    Two things in the history of our planet prove that "Life"  did not evolve but was a product of intelligent design. One, the water here on our planet was the cooling factor in a world that was once Molten. It did not get here by asteroid nor comet, as it would have left a serious dent, as the molten rock would have hardened at the edges of the Ice where it came to rest, and we have no evidence of such a dent. The water is here though, leaving only two possibilities as to how we came to have enough water that if you formed it all into one sphere and place one edge at the east coast of the United states, the other edge would be in Idaho. Either as a liquid, or a Chemical process combining Hydrogen and Oxygen. As water will freeze in space it seems like a large spaceship would be required for liquid arrival. However the Hydrogen and Oxygen would have arrive here at the same time, or both would have just burned off as they are both flammable. Arrival at the same time would require intelligence. So how is this proof that evolution didn't happen? read Genesis, in the Bible, first it was dark and void, and standing on the moon you most likely would not even see the earth. In it's molten state it would still adhere to the laws of Physics, a perfect sphere, and reflecting no light from a black surface, and the only light at all would most likely be at the noonish part or half the day rotation as the back side away from the sun would be as cold as is the dark side of the moon, and would take some time to melt as it entered the suns light. Still it had to be cooled to support the variety of life that exists today. "And god said let there be light". Steam would have reflected light, very effectively, yet that wouldn't follow what the Bible said happened nor would you find the Science supporting a liquid arrival. " And God said, Let there be light: and there was light.

    4 And God saw the light, that it was good: and God divided the light from the darkness.

    5 And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.

    6 And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.

    7 And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so."

    Firmament [N] [S]
    from the Vulgate firmamentum, which is used as the translation of the Hebrew  raki'a . This word means simply "expansion." It denotes the space or expanse like an arch appearing immediately above us. They who rendered  raki'a by firmamentum regarded it as a solid body. The language of Scripture is not scientific but popular, and hence we read of the sun rising and setting, and also here the use of this particular word. It is plain that it was used to denote solidity as well as expansion. It formed a division between the waters above and the waters below ( Genesis 1:7 ). The  raki'a supported the upper reservoir ( Psalms 148:4 ). It was the support also of the heavenly bodies ( Genesis 1:14 ), and is spoken of as having "windows" and "doors" ( Genesis 7:11 ; Isaiah 24:18 ; Malachi 3:10 ) through which the rain and snow might descend.

    Alright, now this isn't a Bible study by any means, so I will get to the point. If water started as a Chemical reaction, you would be able to use the Molten earth itself as the catalyst, and the explosion itself would create the brightest light, but more to the point the water created in the Explosion would have been thrown in every direction and that would include up. the further it got from the warmth of the planet it would have frozen, like a bubble surrounding the earth. Remember, "divided the waters which were under the firmament from the waters which were above the firmament.......

    The other part is Pangaea, yes all the contents of the world fit together like a puzzle, that isn't really all that earth shattering unless you really look at it for a moment. Pangaea, for all that is as an Island, was once a complete sphere unto its self. Look at the land mass up towards Iceland and Greenland and realize it is a crack in the Puzzle. but to bring it together you have to bring the land masses together as a ball, and if you remove that ball from the face you have the earth as a cracked, but perfect sphere. There are over 70 different Myths and legends around the world of this planet having little to no land mass in the beginning, leave us with the question remaining. How could a book no matter how hold it may be, tell of an event that happened before a person could have ever possibly known something that we now face only as theory?

  23. Randy Polzin Randy Polzin United States says:

    In the beginning God created the heavens and the earth.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News-Medical.Net.
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