Posted on 02/03/2005 7:01:32 AM PST by Junior
Jack Szostak and his colleagues at Harvard Medical School are seeking to understand the origin of life through a series of audacious experiments intended to build a basic living cell from scratch (see “What Came Before DNA?” Discover, June 2004). Using a simple experiment, they now demonstrate that one of the key steps—creating a simple growing cell by tucking self-reproducing molecules into a membrane—may be startlingly simple.
The new research rebuts the widespread belief that cells have to evolve elaborate molecular machinery to enable them to grow, one of the basic characteristics of living things. Szostak and his colleagues started with chemicals thought to have been common on early Earth: nucleic acids (the building blocks of DNA) and fatty acids. One interesting property of fatty acids is that they spontaneously form bubbles, or vesicles, that allow water molecules to pass back and forth but trap larger molecules. In the Harvard experiment, vesicles that contained relatively high concentrations of nucleic acids expanded like balloons, while nucleic acid-poor vesicles shrank. The growing vesicles cannibalized fatty acids from the shrinking ones, so they were able to keep growing without popping.
Previously, researchers have shown that some simple RNAs, the smallest about twice as long as those of the Szostak group’s simple cells, can replicate without help from other molecules. The group’s new observation is that packing a membrane with more nucleic acids makes it expand; this mechanism could provide the cells with a simple method for evolutionary competition. If some of these model cells contained nucleic acids that could replicate themselves, even inefficiently, they would have grown at the expense of competitor cells. The more effectively the nucleic-acid molecules can replicate, the more rapidly their surrounding membranes will grow. “What we showed was that you can get a Darwinian competition to emerge just from the basic physical properties of the system,” says Irene Chen, a graduate student in Szostak’s lab. “It doesn’t require biological machinery.”
Ping.
Ping.
Kind of blows away those ridiculous probability caclulations that assume you need to assemble a completely modern cell in one single shot for things to get moving. Not that this will keep us from having to endure them, though.
calculations.
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I can almost guarrantee we won't see a lot of creationists posting on this thread.
thanks for the ping.
forgive me if I don't hang around for the IDers to chime in.
This thread is woefully lacking in creationist canards.
"It's being done in a lab, so it just proves intelligent design!"
There, that's better.
Wow! Great work. Kudos to Jack Szostak and his colleagues.
You are probably right. Most don't even have the chemistry basics to understand this, let alone see how this very basic chemistry has strong biogenisis characteristics. If they do show up, they will likely spout some chemical nonsense that would get them fired if they were employed in a position using the chemical sciences, or at least re-assigned to the back office filing paperwork.
yup, that's ID - see scientist in the lab did it, therefore it was designed. They wouldn't even recognize that it's the chemicals by themselved doing their own organizing. No human hand made or designed them. Humans just put them in a flask and let them do what they do naturally.
Bet you a nickel this will be spam city by this evening.
What, do we have a quota system now or something? ;)
Maybe until then, one of us should play the creationist part. Any takers? No one has brought up the 2nd law of thermodynamics yet... doesn't chemistry violate the 2nd law?
How about "Genesis doesn't mention lipid chemistry, therefore this is totally invalid"?
When the bubbles evolve into little sponge-bobs, wake me up.
I notice Miss Chen did not say "darwinian selection", not that that means too much. It's a interesting experiment. And I wonder if the card shark in the park of eternity is teasing the evos with a few good-looking cards "Look how easy it is to win!" --- the response on thread does so indicate.
Don't talk to me until you've self-organized a protein from scratch.
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