With colleague Tracey Lincoln, Gerald Joyce (picured) has created an artificial genetic system that can undergo self-sustained replication and evolution.
Credit: Scripps Research Institute
SAN DIEGO: Can life arise from nothing but a chaotic assortment of basic molecules? The answer is a lot closer following a series of ingenious experiments that have shown evolution at work in non-living molecules.
For the first time, scientists have synthesized RNA enzymes – ribonucleic acid enzymes also known as ribozymes - that can replicate themselves without the help of any proteins or other cellular components.
What’s more, these simple nucleic acids can act as catalysts and continue the process indefinitely.
'Immortal' molecules
“There’s nothing in biology in this system: no proteins, no cells, no biological matter. We just provide them with the building blocks,” said molecular biologist Gerald Joyce of the Scripps Research Institute in San Diego.
“They’re just molecules, so they do what they do until they run out of substrate. And this will go for ever – it’s an immortal molecule, if you like,” he told a meeting of the American Association for the Advancement of Science in San Diego.
Since he and colleague Tracey Lincoln first succeeded in creating this artificial genetic system that can undergo self-sustained replication and evolution last year, the molecules have changed dramatically as they evolve better and better solutions.
Survival of the fittest
The researchers began with ribozymes known to occur naturally, and put these in a growth medium, heated them and allowed the ribozymes to replicate until they had exhausted their fuel – usually within an hour.
The team then extracted a random subset, and put them in a new medium: ribozymes then competed with each other to consume as much of the medium as possible.
Eventually more successful ribozymes came to dominate the culture, and as the process continued, the ribozymes – undergoing evolution - grew in complexity, blindly finding solutions that made them more successful.
“The key thing is it replicates itself, and passes information from parent to progeny down the line,” Joyce told Cosmos Online.
“There’s roughly 30 bits of information passed. Some functions are more fit than others, and those that are more fit ‘breed’ more, and are perpetuated more efficiently, and so it goes Darwinian.”
The ultimate goal is to create genetic systems that behave like life, and are for all intents ‘life’ as we know it, but arose without using biological systems.
Hype+Buzz Words != Science
Hmmm... sounds fascinating, but reading between the lines, its not really clear what these scientists observed or accomplished beyond a specific type of chemical reaction.
What was the mechanism that allowed these molecules to grow in complexity? What "problems" are they solving? What is meant by complexity? These words are so incredibly ambiguous and overloaded that without very clear definitions and specifics, I remain skeptical.
What was the mechanism that allowed these molecules to grow in c
Ha! It appears someone from Answers in Genesis already on top of this...
In an autocatalysis environment beneficial mutations of RNA strains ( as RNA duplication is not perfect) would be propagated.
Simple
Typically, the measure for something like this (extrapolating from similar DNA experiments) is simply the ability to consume the substrate ("food" if you like). The article mentions that initially the chemical reaction consumed the substrate in 1 hour. The better-adapted molecules consume it faster/more efficiently/prevent others ("starving" competition). By selecting randomly from whatever remains at the end, the most successful (by that simple definition) are statistically more numerous and therefore more likely to be chosen in the random sample.
"Skeptical"? It's science: we're welcome to reproduce the experiments
ourselves, we don't have to philosophize for 100s of years on this one.
Maybe too simple...
The commenter's skepticism wasn't about the facts of the experiment, but about their interpretation.
Re. "complexity", information is one measure, and the 30 bits mentioned in the article isn't a lot.
Re. the topic in general, it should be kept in mind that "evolution", as understood in biology, is about change in genetically based systems, not about how they originated, before biology got rolling.
Prebiotic Evolution
The article shows a major step in chemical evolution, or prebiotic evolution, which necessarily precedes biologic evolution. If a molecule containing genetic information such as a ribonucleotide can 1)replicate, and 2)catalyze its own metabolism, then you have the basis for natural selection and complexity will increase as a result in due time. For example, if any naturally formed ribozymes evolved a lipid membrane to contain their catalysis then they would have a large selective advantage over the promiscuous ribozymes and would be the basis for the first cells. RNA, which contains genetic information, can self-replicate and autocatalyze, as shown by this article. It carries functions of both proteins and DNA that enables natural selection to act upon it.
I Concur
This article lacks descriptive information regarding the actual measurements and methods used to come to these conclusions. Furthermore what are the "evolutionary" assessments? Are they advantageous or positively selecting modifications in replication, or were these "evolutionary" steps random drift in populations?
both
Why do you hate science so much that you need to spout your unfounded fundamentalism here? You are somewhat right though: there are no measurements and methods&materials listed here. That is because it is not a scientific journal it is published in! If you had ever read some, you would have know... As for evolution or random: it does not matter, its both. The mutations are random because RNA replication is a sloppy process. It is through that randomness combined with the experimental setup that the most fit are selected. And as you might know, evolution works trough the selection of the fittest (or slightly reworded: unselection of the unfit).
If you had any real interest in this subject, you could do a simulation on your computer. I don't think you ever will though.
Are you sure it's a fundie?
What if it's a scientist?
You see, in science, unlike in poor rhetoric, there is still a difference between asking for details about an assertion and spouting off a rote contradiction of it.
"You say fitness increased; by what measure?" is an entirely scientific question to ask. It need not imply hostility to the idea, much less to its whole background.
Or, equally valid questions for a philosopher: "Given that this system is not homeostatic, is it really any more life-like than what we had before? We have computer programs that evolve algorithms -- is this an advance merely because you used biological molecules? And in a way, I might add, that's somewhat atypical for modern organisms, i.e. for life as we know it."
Or, for a journalist: "How much of this is the experimenter's own interpretation, and how much of it is yours? How confident are you that you understand what you are reporting?"
I don't see any hatred of science above, nor any fundamentalist claims made. I do see a popularized report of a very cool experiment, then some questions about its interpretation and reporting, and then a couple of would-be defenders of science who seem to have a persecution complex. Relax. Truth will survive, with or without the help of un-proofread put-downs frantically lobbed at anyone who might be from the opposing tribe. So you may as well assume good faith.
You are reading Cosmos
It's Cosmos, not a scientific journal. If you really want to know more about it you could read the paper in Cold Spring Harbor Symposia on Quantitative Biology, or you could click on the link to the Joyce lab at the bottom of the article.
yea well
It's just an explanation for common people to translate the complex process that was performed and its meaningful results.
On the side of religion though the existence, verification or confirmation of evolution wont completely dismiss religion as a whole. Why can't there be a natural process through which an entity such as god works, maybe that's how he created it. Isn't just possible that the bible gives a "sugar coated", simplified version of what actually took place. If you where to explain how you created a moving picture on a wall to people around the time of Christ you would more than likely put it into terms they could understand.
So I implore you, read between the lines, On the first day starting exactly at 12:00 did god create "time" hah, fire, water, dirt and the idea of being late. Or.. maybe it's simply a metaphor explained in a type of representation so us simple mortals can understand the complex processes that went on?
I'm not religious and don't care in much of either direction but, it's just an explanation put out in the world so everyone can understand and fell the importance of the message.
And I tend to a agree with you, what have we really achieved here? I'll start believing its actually evolution when it starts to become something more than building blocks.