Posted on 06/04/2004 8:08:18 AM PDT by Michael_Michaelangelo
It is not often that the audience at a scientific meeting gasps in amazement during a talk. But that is what happened recently when researchers revealed that they had deleted huge chunks of the genome of mice without it making any discernable difference to the animals.
The result is totally unexpected because the deleted sequences included so-called "conserved regions" thought to have important functions.
All DNA tends to acquire random mutations, but if these occur in a region that has an important function, individuals will not survive. Key sequences should thus remain virtually unchanged, even between species. So by comparing the genomes of different species and looking for regions that are conserved, geneticists hope to pick out those that have an important function.
It was assumed that most conserved sequences would consist of genes coding for proteins. But an unexpected finding when the human and mouse genomes were compared was that there are actually more conserved sequences within the deserts of junk DNA, which does not code for proteins.
The thinking has been that these conserved, non-coding sequences must, like genes, be there for a reason. And indeed, one group has shown that some conserved regions seem to affect the expression of nearby genes.
To find out the function of some of these highly conserved non-protein-coding regions in mammals, Edward Rubin's team at the Lawrence Berkeley National Laboratory in California deleted two huge regions of junk DNA from mice containing nearly 1000 highly conserved sequences shared between human and mice.
One of the chunks was 1.6 million DNA bases long, the other one was over 800,000 bases long. The researchers expected the mice to exhibit various problems as a result of the deletions.
Yet the mice were virtually indistinguishable from normal mice in every characteristic they measured, including growth, metabolic functions, lifespan and overall development. "We were quite amazed," says Rubin, who presented the findings at a recent meeting of the Cold Spring Harbor Laboratory in New York.
He thinks it is pretty clear that these sequences have no major role in growth and development. "There has been a circular argument that if it's conserved it has activity."
(Excerpt) Read more at newscientist.com ...
Now we're getting into interesting stuff.
Perhaps -- but the base for the recursion has to contain a huge amount of information. How would it do that, especially since there's no apparent evidence for this fractal approach. Note also that you're basically splicing different parts of the recursion together, and still getting the same result, which isn't how fractals work.
My suspicion is that we're getting ready to learn how little is really understood about the way DNA stores and propagates information.
They created democRATS!
As long as it's used in the correct context, then we are okay. However, when someone describes a particular gene as "junk" when describing a gene with no apparent function (as in broken or non-functional) - they are jumping the gun. If the context is describing a gene with a "yet to be discovered function", then I suppose it's acceptable (although you'd think that there would be a better term out there they could use).
The direction of science cannot be predetermined. To prefer one lame hypothesis over a million other ideas is for 8th grade dropouts who will never even try to do anything their whole pointless lives.
He thinks it is pretty clear that these sequences have no major role in growth and development. "There has been a circular argument that if it's conserved it has activity."
Well, yes. The assumptions are those of Darwinian evolution.---> Things change. Things that are necessary for survival(activity) don't change(conserved).
There is no explanation for this under RMNS. Do you have one?
Not having an explanation is a rather common phenomenon in science. It is only a problem if you assume everything can be deduced from first principles. Otherwise it is merely a new challenge.
Yes, it is a death knell for a theory with the inability to do the explaining.
- William A. Dembski
No, it is a problem when it is not consistent with first principles.
Give it up! In "Stump the Dummies," the first time you don't know the answer, you lose.
Astonishing! So the question shifts from why is this region conserved to how is this region conserved.
Hypothesis: There exists a biochemical toolkit (see, e.g. The Wisdom of the Genes by Christopher Wills) for preserving specific regions of DNA, which prevents mutations from happening on those segments, rather than simply having death weed out changes to those segments. The map of where the toolkit is applied, however, is subject to change through evolution. Some changes to the map are weeded out through natural selection (i.e., changes that withdraw protection from certain vital segments), while others are not (i.e., changes that extend protection over unimportant segments).
You do realize that out of some 26.4 million DNA sequences there are just 1098 known conserved non-coding sequences between men & mice and merely 32 versus non-mammalian vertebrates? Does it not seem quite plausible that random mutation may over the span of however long the lines of man & amphibian diverged managed to randomly conserve 0.000121% of the sequences? Or 0.00416% of the mouse sequences?
Well, that's just one possibility, and that's not even considering the likelihood of some underlying, undiscovered biological function that has lead to their conservation. The scientists have proposed several, and they will be tested in time. Whatever the case, I just wanted to point out that we're not talking about vast tracts of non-protein coding "junk" DNA here..
So here we have proof that huge chunks of DNA are completely unnecessary. So much for being irreducible. So much for showing intelligence in design. I have some of your (now banned) compatriots on record as saying there is no such thing as junk DNA. That is a failed prediction.
To the best of my knowledge, no mainstream biologist is on record as saying that because mutations can occur, they must. The question of why conservation occurs will be settled in the laboratory, someday.
Sucking chest wound treatment
Nope. Read the article. Redundancy.
Oh, I should mention that those figures may be somewhat out-of-date, though probably not by too much (unless there's been some major discovery I've managed to miss).
No.
If you don't think that the unexpected result is the most delightful thing to a scientist, then you understand nothing about science, nothing at all.
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