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)
No, it isn't just a *feeling.* It is a reasonable inference, and it is well within the bounds of science to make such an inference. Now, if you want to declare that it is outside the realm of science to explore matters related to intelligence and how they relate to design, that's fine with me. But I am not the one to tell science what it can or cannot do.
Yep. All for indulging in "non-productive" science.
That isn't quite true. ID literature changes its statements depending on the targeted audience.
Dembski: "Indeed, intelligent design is just the Logos theology of John’s Gospel restated in the idiom of information theory."
Are you being cruel? ;->
I just thought it might be easier to discuss a relevant model that already has a conclusion to compare our points of view to, is all.
WHY do you feel that it would 'drive' someone in the direction you claim?
I'm not sure what you mean by that, but intelligent design is certainly not the basis for all science investigates. IDists are saying that 'what' science investigates contains ID not that science 'uses' ID.
Because of an identical philosophy of reality.
Can you explain to me how you came to have this faith?
This is NOT an answer to my question--what do the verses mean to you?
If you do NOT interpret them 'literally' then what do they mean to you?
In what way? How do you define 'organized'? Is a crystal 'organized'? Is an molecule organized? Is an atom organized? Is DNA organized?
"That implies design.
Why?
It's this 'accomodation' that has screwed up the church of today!
Accomodation to accept abortion...
Accomodation to accept homosexuality...
Accomodation to accept the worlds view on most everything...
;^)
Hey, you were the one to equate "my tactics" with those of liberals. What is that but a personal attack? You support the fraudulent notion that intelligent design is beyond the merits of scientific consideration. You consider my reasonable inference that organized matter implies a designer to be a matter of elevating "feelings" over "fact." You consider your own point of view as the only one worthy of discussion in the schoolroom and thus intellectually superior.
Kindly retract your insidous notion that I argue like a liberal if you wish. The label applies better to yourself.
Actually, in retrospect, I don't mind the ad hominem attacks so much. After all, they are not the sole property or tactic of liberals, and I've dished out more than my share.
Again, let's deal directly with Behe's hypothesis: that the actions of a designer are a "necessary" ingredient in the development of flagella. That claim is testable, and it's falsifiable -- which is something that is often raised as "the standard" for a scientific theory.
No argument here, but that doesn't help Behe's point.
It helps his point quite a bit more than if it were demonstrably impossible to construct flagella. Feasibility is an excellent way to determine whether a hypothesis is valid in the first place. Indeed, one of the "problems" with ID (if you want to call it a problem) is that design is an inherently plausible hypothesis -- we look at problems through the lens of how we might design a solution. A commonly seen argument against ID has the form, "God would have had to have been stupid to do it this way -- I would have done it this way," which is in large part a confirmation of that plausibility.
The problem here is that his argument of "necessity" is flawed from the *start*
Maybe so -- but again, it's a testable statement. If his claim is flawed, one can perform tests to disprove his claim.
No it wouldn't, and therein lies the whole problem. There is no "necessity" of ID even if one could prove beyond all doubt that the flagella could not have evolved.
If you could demonstrate that, you'd be left with a need to propose some non-evolutionary means by which it occurred. A highly plausible alternative (based on a relative confidence that humans could do it) would be design.
Likewise, there is no "necessity" of Evolution, even if one can prove beyond all doubt that some things did evolve. The existence of the biotech industry demonstrates this: biotech products are an example that not all things evolved.
They falsely presume that there are only two possible explanations: a) evolution, or b) design.
And you seem to be saying that there's only one possible explanation worth exploring, which is also false. Be that as it may, can you propose some third or fourth possible explanation?
Indeed, this could (depending upon the exact nature of that discovery) be a falsification of at least part of evolutionary theory. But no such test has yet been proposed for ID (or at least no such test that actually holds up under examination).
The question is, though: was such a test performed for the hypothesis of evolution? If so, what were the results? If not, why not?
Oh...
THIS sample set is not skewed!
I report...
they decide.
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