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To: SengirV
And now that it’s 6%, does it really make all that much of a difference?

It may make a very large difference. There are separate fields of science which must be in agreement as to a time line for natural selection to be convincing for the origin of particular species. These are different fields such as the geologic record, the fossil record, and genetics.

When comparing two species and trying to look backwards in time to when they "split" from a common ancestor, scientists can compare the DNA and find how many genes are different between the two species. There are models of how fast genetic mutations can be propagated through a population, given factors such as population size and the lifespan of the individuals. With these, we can backtrack to estimate when these two species had a common ancestor.

By increasing the number of differences, natural selection proponents must also have to increase the amount of time required to propagate those changes. I would guess that previously, scientists probably would have claimed to the public that the fossil record and the DNA record were in agreement for chimps and humans. By increasing the number of differences by 600%, is that still a true statement? Has there been enough time in the fossil record to account for this? What now is the estimated date these two species had a common ancestor? Is it millions of years ago? Is it hundreds of millions? Did apes even exist in the fossil record back then?

This is the same reason why the recent new findings of "junk DNA" are important. The claim of junk DNA can be misused by scientists as a fudge factor if all the sciences do not agree on a time scale. Recent findings have been chipping away at what can be considered junk, and added to the pile of what must be accounted for in the other sciences. All the recent genetic findings that I have seen published have increased the amount of time required by natural selection.

129 posted on 07/10/2007 6:43:27 PM PDT by Vince Ferrer
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To: Vince Ferrer

And moving the common ancester time back effects the anti-”church of Darwin” folks how exactly? That was my original point. I realize the timeframe of such connections get pushed back, but does 10 million as opposed to 2 million really make that big of a difference in the overall scheme of things? The anti-”church of Darwin” people seem to think this is a smoking gun as to the irrelevance of a human/chimp conneciton, when in reality it is not.


154 posted on 07/11/2007 6:24:14 AM PDT by SengirV
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To: Vince Ferrer

“There are models of how fast genetic mutations can be propagated through a population, given factors such as population size and the lifespan of the individuals. With these, we can backtrack to estimate when these two species had a common ancestor.”

Do these models work any better than the climate models that the GW religionists use? :-)


157 posted on 07/11/2007 7:02:48 AM PDT by webstersII
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To: Vince Ferrer
Has there been enough time in the fossil record to account for this? What now is the estimated date these two species had a common ancestor? Is it millions of years ago? Is it hundreds of millions? Did apes even exist in the fossil record back then?

You're oversimplifying things. Depending on what you're looking at in the genome the difference between us and chimps may be 1%, 5%, 6%. . . Any of the various methods of calculation are correct, and none of them really are useful for understanding how our genomes compare. The smallest differences come from gene sequences, when you start to look at other sequences and chromosome structure it becomes puzzling how to calculate the difference. We have one chromosome that is a fusion of two ape chromosomes, how do you calculate that? How about the sections of our chromosomes that are inverted compared to apes? How do you account for individual polymorphisms, which there are many in both humans and chimpanzees?

Basically all of the twiddling about trying to calculate exactly how different our DNA sequence is compared to chimpanzees doesn't change a thing. Chimpanzees and humans shared a common ancestor about 5-7 million years ago (there was probably an earlier split with the two ancestral populations hybridizing until about that time). This is consistent with the fossil record and with genetic evidence.

160 posted on 07/11/2007 8:10:43 AM PDT by ahayes ("Impenetrability! That's what I say!")
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