Posted on 11/16/2005 3:40:35 AM PST by snarks_when_bored
* 14:02 15 November 2005
* NewScientist.com news service
* Gaia Vince
A new microscope sensitive enough to track the real-time motion of a single protein, right down to the scale of its individual atoms, has revealed how genes are copied from DNA – a process essential to life.
The novel device allows users to achieve the highest-resolution measurements ever, equivalent to the diameter of a single hydrogen atom, says Steven Block, who designed it with colleagues at Stanford University in California.
Block was able to use the microscope to track a molecule of DNA from an E.coli bacterium, settling a long-standing scientific debate about the precise method in which genetic material is copied for use.
The molecular double-helix of DNA resembles a twisted ladder consisting of two strands connected by “rungs” called bases. The bases, which are known by the abbreviations A, T, G and C, encode genetic information, and the sequence in which they appear “spell out” different genes.
Every time a new protein is made, the genetic information for that protein must first be transcribed from its DNA blueprint. The transcriber, an enzyme called RNA polymerase (RNAP), latches on to the DNA ladder and pulls a small section apart lengthwise. As it works its way down the section of DNA, RNAP copies the sequence of bases and builds a complementary strand of RNA – the first step in a new protein.
“For years, people have known that RNA is made up one base at a time,” Block says. “But that has left open the question of whether the RNAP enzyme actually climbs up the DNA ladder one rung at a time, or does it move instead in chunks – for example, does it add three bases, then jump along and add another three bases.
Light and helium
In order to settle the question, the researchers designed equipment that was able to very accurately monitor the movements of a single DNA molecule.
Block chemically bonded one end of the DNA length to a glass bead. The bead was just 1 micrometre across, a thousand times the length of the DNA molecule and, crucially, a billion times its volume. He then bonded the RNAP enzyme to another bead. Both beads were placed in a watery substrate on a microscope slide.
Using mirrors, he then focused two infrared laser beams down onto each bead. Because the glass bead was in water, there was a refractive (optical density) difference between the glass and water, which caused the laser to bend and focus the light so that Block knew exactly where each bead was.
But in dealing with such small objects, he could not afford any of the normal wobbles in the light that occur when the photons have to pass through different densities of air at differing temperatures. So, he encased the whole microscope in a box containing helium. Helium has a very low refractive index so, even if temperature fluctuations occurred, the effect would be too small to matter.
One by one
The group then manipulated one of the glass beads until the RNAP latched on to a rung on the DNA molecule. As the enzyme moved along the bases, it tugged the glass bead it was bonded too, moving the two beads toward each together. The RNAP jerked along the DNA, pausing between jerks to churn out RNA transcribed bases. It was by precisely measuring the lengths of the jerks that Block determined how many bases it transcribed each time.
“The RNAP climbs the DNA ladder one base pair at a time – that is probably the right answer,” he says.
“It’s a very neat system – amazing to be able see molecular details and work out how DNA is transcribed for the first time,” said Justin Molloy, who has pioneered similar work at the National Institute for Medical Research, London. “It’s pretty incredible. You would never have believed it could be possible 10 years ago.”
Journal reference: Nature (DOI: 10.1038/nature04268)
Perhaps not elves, but some kind of designer. There is scientific reason to infer that a designer may be responsibile for matter that is organized and performs numerous, specific, functions beyond the capacity of intelligent humans.
No pictures?
Fine; drop the reference to "religion" - the complaint remains the same: a fascinating scientific breakthrough is described, then you suddenly go on a non-sequitor bashing rant ... and now seem to reveal an even more subversive goal to observe perceptive links between ID & religion.
Shoulda left it at observing DNA duplication. That would have made for a fascinating thread.
And prevent most, if not all, wars.
Not until credible evidence is found to support your hypothesis. This has not occurred.
Why not elves? Elves are superhumanly intelligent in a manner you cannot comprehend.
There wouldn't be an anti-evo group.
Besides you missed the reference to Dickens. Shame on you. And at the Holiday Season, as well.
Tsk. Tsk. Tsk.
When you're faced with bare facts, the aspect of falsifiability is moot. Shall we exclude bare facts from the realm of "scientific" because they are "unfalsifiable?"
Or maybe you don't believe in bare facts.
I guess you know more about elves than I do. I've assumed them to be fictitious. You apparently assume otherwise.
Thunderous placemarker
Wow. That's an amazing reach.
Falsifiability applies to theories. Whatever else it to which it may or may not apply is irrelevant. All theories need to be falsifiable - that's what makes them theories.
Facts don't need to be falsifiable. Theories do. Or do you not understand the difference?
I don't think you are right.
We now see how genes are copied through a molecule of DNA and "how" life is created through a chemical process and not some supernatural power.
Later on in this thread there is a discussion of how DNA duplication will have an error every so often.
It seems to me that this is pretty damning to the creationist cause.
Sigh. Do you ever converse without tossing insults into the mix? Is it simply impossible for you to hold a civil conversation? Or is it your normal approach to attempt to bully others into submission?
While Hitler may have used parts of the Bible to justify his "master race" theories, it is not true that they were inspired by the Bible. People use the Bible to justify all sorts of things that are not in accord with the tenets espoused therein. It would be best for you to avoid accusations of "simplistic" until you can avoid the same sin.
The 100 million corpses evokes the history of Communist China, Communist Russia, Communist Vietnam, Communist Cambodia, Communist North Korea.... All avowedly atheist. And they didn't really rely on modern technology to do it, either, except perhaps the use of firearms rather than swords.
And if you want to compare apples to apples, just think how the numbers would compare if past "warriors for God" had had access to modern technology when they set out to slaughter the "heretics" or sacrifice the unworthy to their gods.
They weren't exactly "warriors for God," but Ghengis Khan and Attila the Hun were very effective in their use of large-scale killing, and they didn't use high-tech weapons to do it. Your appeal to high technology is thus somewhat irrelevant; further, it merely points out something else: people are willing and able do really bad things and always have been.
-- why is it that it's the *creationists* who lie so frequently and unashamedly on these discussions, and not the allegedly "godless" evolutionists? Please explain.
I guess this thread exposes you as a creationist. Please advise.
No less arrogant and ignorant than considering one's own interpretation of the Bible to be the final word for the rest of mankind.
"When you're faced with bare facts, the aspect of falsifiability is moot."
What bare facts would those be?
I don't recall stating a hypothesis. I do see credible evidence for a designer. I cannot deny that matter demonstrates design and order in a manner and degree that causes me to infer a designer is involved with it. It is hardly unreasonable or unscientific to make such an inference. And inferences, just like falsifiable declarations, are part of science.
It is not the burden of ID to prove itself "scientific." It is the burden of evolutionists to prove why science must, by definition, operate disctinctly from anything ID might entail. They haven't even come close. They're too busy casting aspertions upon the motives of those who merely state the obvious: the evidence of intelligent design is more voluminous than the evidence for its opposite.
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