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.
Hitler based his "master race" idea on the Bible. What does that do to your childishly simplistic analysis?
Another problem with your goofy argument is that a very small handful of tyrants have managed to rack up large totals in this century because of the realities of modern warfare, but this does nothing to support the assertion that the 99.9+% of the "godless" who haven't committed genocide are somehow less ethical than the 99.9+% of the "godful" who haven't run Inquisitions. It's a gross fallacy (and grossly dishonest) to try to "measure" the general level of ethics of any large group by the behavior of a very few extreme cases.
A further problem with your laughable "analysis" is that you're dishonestly restricting the genocide comparison to the 20th Century -- but for thousands of years, mass slaughter at the hands of believers in a God has been racking up countless victims. I'd be amazed if the grand total didn't easily far exceed 100 million, so you might want to rethink your metric.
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.
Finally, your desperate attempt to distract from the question by pointing to a few mass murderers just doesn't answer the question -- 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 don't think it's possible. At least not with our star. Maybe if we lived within a Dyson sphere and collected all the energy... but then again...
Or had a catalyst of some sort...Hmmm...
Actually, he only critiqued the "ID hypothesis", he made no mention of any religion. The IDers keep trying to claim that theirs is *not* a religious research program.
But by your response, clearly that's just a "wink wink nudge nudge" position. Everyone understands that "ID" is synonymous with religious creationism, as your reaction demonstrates. Say something against "ID", and a dozen people spring out of the woodwork complaining about how their religion is being denigrated...
I saw a documentary on PBS (Oh, no!!) about the spread of Islam. Estimates were 20-40 million killed during its rapid spread.
People are dangerous and they will use whatever is at their disposal to inflame the idiots to do their will. No particular group has a monopoly on that.
There is none.
Thank you. And this is why "ID" isn't science, isn't scientific, and doesn't belong in science classrooms. It's an untestable postulate.
Your suggestion that science should be defined by non-scientists is like suggesting that brain surgery be defined by pianists. If you want to get in on who defines science you'll have to become a scientist. And, for you, that'll take a lot more education to gain the credibility you lack in this discussion.
I bet pianists could make good brain surgeons. They'd have the fine motor skills necessary.
Behe has suggested that the flagellum would be a great test. Given advances in nanotechnology and microbiology, one can at least plot out a path to constructing them, probably within the next 20-50 years. The ID hypothesis could be falsified if one were to construct a test whereby we could observe flagella developing through a process of evolution. Behe's claim that ID is "necessary" for the development of flagella would be invalidated.
Which of course raises a corollary question: the current hypothesis is that flagella evolved. Has anybody ever tested it?
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.
Nope. You've overstepped your assumptions here. It's true that many religious people are at least open to the possibility that God did it all (and many even demand it). From a strictly scientific perspective, however, it is not necessary to invoke God in order to make an ID claim (bioengineering is an example of this). Nor is it necessary to assume that ID and Evolution are mutually exclusive processes.
Your assumption about sudden change in the fossil record is false. The changes described by creationists as "sudden" take tens of millions of years.
It's not "my assumption." Leaving aside the merits of the theory itself, the folks who thought up "punctuated equilibrium" were responding to a perceived problem with the ToE, as it shows up in the fossil record; namely, how to account for a fossil record that showed long periods of stasis, followed by relatively sudden sharp changes. They were concerned about this -- it didn't match the "slow and gradual" hypothesis that even now pervades the popular view of Evolution.
and my response was that a DNA retrovirus in both gorillas and humans but not chimps would neatly falsify ToE.
It wouldn't "falsify" the ToE, for which there is other supporting evidence. It would do no more than to disrupt the currently held belief about how humans and apes evolved, and would be announced in headline fashion along the lines of "Scientists forced to rethink human ancestry." It might also suggest that there was a mechanism other than evolution involved in that particular characteristic -- but the question in that case would be: what other mechanisms would you allow to be hypothesized?
Famously. Improve rationality too.
And lower the surplus population.
Wrong. Falsifiability does not define science. It is only one tool among many that science uses.
If past threads are any indication, Tallhappy enjoys playing the "you're stupid and I'm not" game a lot more than he enjoys actually adding useful information to the discussion.
All he's really bitching about here is that snarsk_when_bored used "RNA" as a shorthand for "RNA polymerase" (which he correctly referred to at the start of his paragraph, and was clearly the subject of his following discussion), when he should have used "RNAP".
Tallhappy likes to insult people by accusing them of vast ignorance and a complete lack of education on a topic whenever he catches them at something as trivial as a minor slip of terminology.
There's a word for people like this, and it starts with an "A".
...and you've demonstrated *such* a comprehensive and accurate understanding of science on these threads...
I never said it defines science, Fester. Try to keep up. But a hypothesis which cannot possibly be falsified *is* still a nonscientific one. And an utterly useless one as well.
No, it is not. I do not have to know all the rules of football to know when the game is not being played right. I do not have to be a concert pianist to know when the pianist makes a mistake in his performance. I do know that science does not rule things out as "unscientific" simply because they are not yet known. Science defines itself as it moves on, despite narrow minds like yours.
Falsifiability might not define science per se, but it does in part define what is or is not a scientific theory.
I thought that too, but wasn't sure I wanted to go there. The anti-evo group have a tendency to point things out we say in jest as something seriously evil.
Perhaps, but it also does not include them as subjects of scientific study if there's no reason to believe they exist. Science doesn't investigate the likely properties of elves, fairies and leprechauns, because there's no scientific basis to anticipate their existence.
Just like ID.
Your verbal semantics are amusing, but they do not make your case. "Falsifiabiliy" does not define something as either scientific or unscientific. ID does not have to have a falsifiable hypothesis to be scientific. Neither does evolution.
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