Chemicals That Evolve in the Lab May Simulate Earth's Earliest Life

By Eliza Strickland | January 12, 2009 10:00 am

test tubesBy tweaking chemical strands of RNA, researchers have taken another step towards understanding how life may have first evolved on our planet. A test tube based system of chemicals that exhibit life-like qualities such as indefinite self-replication, mutation, and survival of the fittest, has been created by US scientists…. “This is the very end of the line, where chemistry starts turning into biology” [Chemistry World], says researcher Gerald Joyce. Researchers have previously created RNA strands that replicated themselves for a while before grinding to a halt, but this experiment marks the first creation of RNA strands that continue to replicate themselves indefinitely, which set up the conditions that allowed for evolution.

In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life [Astrobiology Magazine].

In the experiment, reported in Science [subscription required], Joyce and his graduate student Tracey Lincoln set out to test the RNA World hypothesis. They created pairs of enzymes that can only reproduce with each other’s help, and set them swimming in a pool of RNA fragments that the enzymes could use to build new strands. The enzymes got busy replicating, but sometimes an enzyme would make a mistake as it assembled a strand and a “mutation” would arise.

Most of these mutations went away quickly, but — sound familiar? — some of the changes ended up being advantageous to the chemicals in replicating better. After 77 doublings of the chemicals, astounding changes had occurred in the molecular broth. “All the original replicators went extinct and it was the new recombinants that took over,” said Joyce. “There wasn’t one winner. There was a whole cloud of winners, but there were three mutants that arose that pretty much dominated the population” [Wired News]. But experts say this experiment doesn’t settle the question on the origin of life on Earth, as some unknown type of self-replicating molecule must have preceded the RNA strands.

Related Content:
80beats: Devastating Meteorite Strikes May Have Created Earth’s First Organic Molecules
80beats: New Results from a 1953 Experiment Offer Hints to the Origin of Life
80beats: The Earth’s Oldest Diamonds May Show Evidence of Earliest Life
DISCOVER: Did Life Evolve in Ice?
DISCOVER: The Soak-and-Bake Origin of Life
DISCOVER: The First Cell

Image: iStockphoto

CATEGORIZED UNDER: Living World
  • Tim

    This is laughable…”…has been created by scientists”…in other words, RNA and the chemicals associated with this experiment didn’t appear out of thin air (or a “big bang”), nor can they “tweak” themselves. This whole experiment could not have happened without help from outside intelligence, which is a great indication of how everything came to existence in the first place. Stop trying to use this garbage as evidence for “evolution” and “the big bang”. It’s not science, it’s conjecture and a desperate attempt to make the evidence fit your assumptions and beliefs.

  • Damian

    Tim, if they were claiming they had found the origin of life, you would be correct. But, as it clearly states in the article: “this experiment doesn’t settle the question on the origin of life on Earth, as some unknown type of self-replicating molecule must have preceded the RNA strands”.

    In other words, the scientists recognize the role they played in tinkering with the starting conditions of their experiment, and thus recognize that at most they have found a plausible mechanism for RNA to begin a life chain (as opposed to finding a way for all life, or even such an RNA biosphere to begin from scratch).

    This is the clear and overt conclusion of this article; your misunderstanding may be based on your perceiving some statements that weren’t there, or misinterpreting others. Perhaps you should examine your assumptions and beliefs.

  • Bill C.

    Man, Tim, if only we could have seen that happen to begin with. Can you imagine the size of that test tube?

  • Tim

    Good point Damian, but I disagree…the article leaves no room for an Intelligent Designer–which would be the obvious answer. As you pointed out, it states: “this experiment doesn’t settle the question on the origin of life on Earth, as some unknown type of self-replicating molecule must have preceded the RNA strands.”

    Tell me, where would this self-replicating molecule come from, since neither matter, energy, or life simply appears ex nihilo? The impossibility of abiogenesis and the Law of the Conservation of Energy apply here.

  • Tim

    Bill, I laughed. Great stuff!

  • Damian

    Tim: “Tell me, where would this self-replicating molecule come from, since neither matter, energy, or life simply appears ex nihilo? The impossibility of abiogenesis and the Law of the Conservation of Energy apply here.”

    That’s a cosmological question, and if you’re asking me to explain the Big Bang, I’m afraid I have nothing for you; creating the universe remains science’s greatest mystery. Of course, a lack of evidence should not be construed as evidence of a Creator. Lightening and comets used to be mysteries, too, but we’ve found logical explanations for those.

    However, if you want a cogent explanation of how to get from the Big Bang to organic chemistry, I might recommend Atom, by Laurence Krauss (http://www.amazon.com/Atom-Single-Oxygen-Journey-Earth/dp/0316183091).

    There will always be blind spots in human understanding; it’s your prerogative to attribute those blind spots to an intelligent designer, but that is not a very useful technique for explaining or understanding them. If these scientists have indeed explained how a purely chemical system can develop biological behaviors according to physical laws, that is a useful and enlightening development, surely.

  • Eric

    I’d like to remind people of Stanley Miller’s experiment of freezing glass vials of ammonia and cyanide, similar to atmospheric gases found on early earth, and letting them sit by themselves for 25 years without human interaction other than making sure that they stayed frozen.

    http://discovermagazine.com/2008/feb/did-life-evolve-in-ice/?searchterm=amino%20acid%20formation

    Within a very short time of 25 years amino acids and nucleobases had formed by themselves. What would happen if this was left for hundreds or thousands of years?

  • Jamie

    Damian-

    You got it exactly right. I was going to leave a comment refuting Tim’s 2nd post, but you summed up my thoughts nicely. Essentially, what Tim is doing is presenting a false dichotomy. He rejects the scientific hypothesis presented in the article and then concludes there can be only one alternative, an intelligent designer. Science has not answered this question fully and in the future we may find that this theory was utterly wrong, but it is intellectually dishonest to assume that because science has proven something that an intelligent designer is responsible.

    I do wish to elaborate on Tim’s 2nd paragraph. Tim, you make another bad assumption which I believe is called special pleading. You flatly state that abiogenesis is not possible (with no evidence) yet assert that the Intelligent Designer exists, also with no evidence. You also state that energy/matter cannot be created from nothing but you fail to recognize that you use the same assumption regarding your Intelligent Designer, that he/she/it exists with no cause. And if the Designer can exist without cause why not energy and matter as well (not to mention there are hypothesis about how energy can spontaneously appear through quantum fluctuations where previously nothing existed)

    I’ve seen people pull this trick before. They demand an answer to a huge scientific question(s) (in this case both, “How did life begin” and “How did the Universe begin”) and when the response is ignorance (as it should be) they claim victory.

    Lastly, I personally dislike armchair scientists who ‘learn’ (often times their knowledge is incomplete or just plain false) bits and pieces of evolution theory (for example), and use that apparent knowledge to support their own ends (Intelligent design in this case). They think science is on their side and even make sure to utilize the scientific lexicon, but ultimately they only convince each other and harm the understanding of the non-scientifically minded person.

    Sorry for the rant and the excessive use of parenthesis, my thoughts were scattered.

    PS. Eric, I’ve read that article and it was quite interesting.

  • Jayson o.

    this article is right about the organisms in our dna

  • Jayson o.

    good article about important science things

  • tatiyana B.

    this is a great discovery

  • Kari M.

    i don’t understand this? but good try……..

  • seth w

    yea right

  • Travis

    There will always be blind spots in human understanding; it’s your prerogative to attribute those blind spots to an intelligent designer, but that is not a very useful technique for explaining or understanding them. If these scientists have indeed explained how a purely chemical system can develop biological behaviors according to physical laws, that is a useful and enlightening development, surely.

  • Amber D

    i’m confused..but it sounds to me like it’s impossible to determine Earth’s earliest life.

  • Damian

    Travis, I am going to presume your imitation is the sincerest form of flattery.

  • travis

    i just did it cause my teacher told us to write stuff
    so i copied yours cause it looked smart

  • Chandler brown

    dude travis could care less if he copyed you so dont feel flattered

  • Chandler brown

    There will always be blind spots in human understanding; it’s your prerogative to attribute those blind spots to an intelligent designer, but that is not a very useful technique for explaining or understanding them. If these scientists have indeed explained how a purely chemical system can develop biological behaviors according to physical laws, that is a useful and enlightening development, surely.cosmological question, and if you’re asking me to explain the Big Bang, I’m afraid I have nothing for you; creating the universe remains science’s greatest mystery. Of course, a lack of evidence should not be construed as evidence of a Creator. Lightening and comets used to be mysteries, too, but we’ve found logical explanations for those.

    However, if you want a cogent explanation of how to get from the Big Bang to organic chemistry, I might recommend Atom, by Laurence Krauss (http://www.amazon.com/Atom-Single-Oxygen-Journey-Earth/dp/0316183091).

  • chris

    There will always be blind spots in human understanding; it’s your prerogative to attribute those blind spots to an intelligent designer, but that is not a very useful technique for explaining or understanding them. If these scientists have indeed explained how a purely chemical system can develop biological behaviors according to physical laws, that is a useful and enlightening development, surely.

  • catherine T

    why cant they leave everything alone and find new things?

  • http://crowlspace.com/ Adam

    God is described as creating all of us – not just one man – direct from the dust in the Bible. Yet we all know we came from our mother’s womb. Perhaps expecting divine special effects in the Creation of Life is missing how God really does things in the world all around us, all the time. Job’s friend called the clouds a mystery beyond human understanding, but we know how clouds form these days, but then perhaps we’re missing the point of what ‘God’ really means.

  • Tim B.

    This is laughable. First they did not start with a purely chemical substance, they started with a purely biological substance RNA. I believe in evolution, Macro and Micro, but I do not believe in the spontaneous generation of life. I have two problems with spontaneous generation:

    First that chemical suddenly came to life and secondly these chemicals were somehow able to house that life and reproduce.

    If chemicals can suddenly come to life then lets reproduce it in the lab. All the elements that have ever existed are still around today, so why can’t we do it. I think that if it happened in the beginning that it would have had to happened over and over and over, millions of times probably, before it ever survived. And if it happened that many times then it can not that difficult to reproduce. As far as needing some primordial soup are some extremely high pressure, what would be in this soup that we don’t have on the periodic table and I don’t really think that extremely high pressure is the best place to cultivate life?

    I guess the thing that I am really stuck on though is the second part where a chemical that has never been alive could house life. Maybe someone can explain to me why this is not impossible.

    And as a side not to call evolutionary biology or even regular biology science is ridiculous, at the best biology is pseudo science. There are three pure sciences: Mathematics, Chemistry and Physics.
    Anything else is just pretending.

  • Mike

    THe scentists included strands of RNA in mix of enzymes.

    So this proves nothing.

  • Matt L

    You know what I don’t get? This whole, entire “but how does life arise from chemistry?” argument. It seems that almost everybody is entirely too myopic about the subject. Life doesn’t arise from chemistry. Life IS chemistry. There is no concept of “alive” in physics, and chemistry arises from physics. There is no concept of “alive” ANYWHERE until people impose a definition to explain a macroscale perception from a top down view. We define life, essentially, as chemistry of sufficient complexity. Yes, we use more careful terms and are careful to exclude any mention of chemistry anywhere in the formal definition, but so far nobody has found any life that isn’t chemically based. A lot of the contention in the memes of the modern world arise from conflicting attempts to explain macroscale phenomena from a top down viewpoint… the Universe doesn’t work top down, it works bottom up. Coming from the bottom up view, the idea of “life” is pretty crazy. Complexity arises naturally in this Universe, see the work of Stephen Wolfram for reference. It arises from the very nature of mathematics, with very simple rules. Repeating patterns, terminating patterns, and non-repeating non-terminating seemingly random patterns appear. Given a large enough workspace (and the Universe is obviously sufficiently large… you’re here reading this, aren’t you?), the complexity ramps up further and further… it’s just an application of evolution, the terminating patterns terminate, the rest continue existing and interacting. Eventually, the complexity aggregates enough to be self-sustaining, reproducing, and highly active. “Life.” Think about the world on the monocellular level… the actual atoms in a bacterium are constantly in flux, new ones enter, old ones leave, but do they somehow gain or lose some property of being “alive?” No. It is the pattern that matters, the bacterium is alive. Not even the DNA and RNA are alive, according to the definition.

    Your mom lied to you. You are not special.

    Oh, and, Tim, I hate you. Go read the definition of the Scientific Method. If you can understand it, you will see how biology (including evolutionary biology, which has many PREDICTIONS which have been TESTED and PROVEN) is in fact a science. I hate people who can’t understand the differences between “hypothesis,” “Scientific Law,” and “Scientific Theory.” Which one is the strongest? The Theory.

  • Matt L

    Since that last post was getting a little long, I figured I’d put this in another post:

    Yes, matter and energy do arise ex nihilo, they are called virtal particles, and they have been found experimentally. If you move particles with mass at near the speed of light, Heisenberg’s Uncertainty principle allows for the possibility that their speed could actually PASS the speed of light. The prediction was that a pair of particle & anti-particle would then be created and subsequently destroy each other, releasing energy. This energy can be measured by the Casimir effect.

  • Matt L

    Virtual particles. Please forgive the typos.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

80beats

80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »