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)
Because the allegedly godless are about 100 million corpses ahead of the rest of us.
Only on FR can a party of one goofball pretend to be a crowd.
Ping.
Oh, great. Now, I'm a mass murderer. :\
Thank you for sharing your presumptions with us.
On the contrary, however, the atheists I know personally are on average more ethical than the Christians I know personally.
I've been thinking about hate and fear a lot lately. I think hate comes mostly from fear. On these threads the fear is mostly a fear of the darkness (self imposed ignorance). Instead of trying to light up the darkness, those that fear huddle in a corner and quiver.
Near as I can tell the cause is hormonal. I recommend removing the endocrine system of everyone who is afraid (OMG I guess I have "NO boundaries").
You pick something, any aspect of ID as proposed by Michael Behe, and show how it could be falsified by an observation.
As to methods, we can potentially gain an idea of what examples of ID might look like, as we've got examples of human ID (e.g., genetic engineering) where we know the answers up front. If it is possible to formulate set of tests that reliably identify human-caused changes, then at least in theory we could attempt to test other phenomena using the same techniques. A positive result would be very interesting. A negative result would be interesting, too.
When someone has actually done that work come back and report. Problem is identifying human design is relatively easy. ID'ers believe that the designer is the God of the bible, in which case everything in the universe is designed in which case your design filter, if correctly designed should show that. Hardly a useful conclusion. How would you know that it was working?
By the same token, I could ask the same question of you: what conceivable observation could show Evolution (as an over-arching explanation) to be false? For example, if the fossil record were to show sudden sharp changes, rather than a slow and steady progression of accumulated changes, would the Theory of Evolution be falsified? We know the answer to that is "no." The response was, rather, to adjust the theory to match the observations.
I think you've asked me that question before, and my response was that a DNA retrovirus in both gorillas and humans but not chimps would neatly falsify ToE. Likewise any chimera that didn't fit into the tree of life. Your assumption about sudden change in the fossil record is false. The changes described by creationists as "sudden" take tens of millions of years. No dogs giving birth to cats, I'm afraid.
Note also that there are some on these threads whose arguments against ID include a claim that one could not recognize ID even if it did occur. Think about that for a moment: what does such a claim imply for evolutionary theory?
I've no idea. Evolution is perfectly easy to recognise and millions of data-points that could potentially have falsified it have instead supported it. To the extent that even the leading ID scientific luminaries acknowledge that evolution is true, and that the Designer has not interfered (as far as they can see) for hundreds of millions of years.
Anyway, lets see that test for ID, a real-world observation that would show Behe to be wrong, for example.
Problem is, not everyone is familiar with the physical evidence. From the evidence of these threads many people's view of the theory of evolution is a cartoon one. Elsie's arguments might be quite effective in getting those people to reject evolution. Hence my concern.
But hey! Its all right, because God will lovingly send you to hell.
To start with, ID is not what you say it is. For instance, there is no rational or scientific reason to demand that evolution and ID must be mutually exclusive. And yet you do seem to demand that.
It is possible -- indeed, given the existence of a vibrant biotech industry it is necessary -- to acknowledge that both mechanisms are valid, and that they can both be operational at the same time.
I have never, ever denied the existence of a class of creationists of the sort you've mentioned here. The problem is, I'm not one of them, and neither are a lot of the people you're attempting to tar with the same brush. I've reminded you of the distinction several times, and you seem to have ignored it. One begins to wonder if your ignorance on this distinction is innocent and honest.
When you can discuss this rationally, honestly, and like an adult, please check back. As it is, you're acting no better than the creationists you claim to be against.
No less arrogant and ignorant than considering one's own definition of science to be the final word for the rest of mankind.
LOL.
If I had been drinking something when I read your post you would have owed me a keyboard.
LOL!!
I wonder if I have an equation for that somewhere...
But be careful with the energy release once they are over the hump. Don't want you blowing the planet up.
There is none. Observation cannot even take place without intelligent design. It is the given with which science operates. There is no observation either, that can disprove the notion that all we see is the result of an infinite combination of matter over an indefinite period of time cause by some unguided process. Fasifiability is only one logical tool of science. It does not DEFINE it.
Nonsense. I'm not evading. I quite clearly said that I believe it to be parable. So all those verses you guys keep posting, with all the "one man" in red, I believe that in that context the phrase "one man" is poetic and not literal, just as the word "Man" with a capital-M is used to represent "mankind" and not one man in particular.
Now that I've clarified my position, will creationists stop lying about the Theory of Evolution and the wealth of evidence behind it?
The article was great ... until you started bashing religion for no apparent reason.
Non-sequitors do not make for interesting intellectual discourse.
In fact Behe has already stated, under oath, that ID requires no physical observations.
It would work, wouldn't it?
If you find one, it'll probably ask you to divide by zero.
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