Posted on 10/02/2001 3:15:13 AM PDT by Ada Coddington
Scientists Find No Genetic Evidence For Evolution
by Bill Sardi
Critics of Darwin's theory of evolution point to flaws in the fossil record (no new species, no missing links) as evidence that the theory is false. But in the 1960s scientists discovered genetic material called DNA and were quick to suggest that the rate of change in DNA is evidence that confirms Darwin's theory of evolution.
While it is convenient for evolutionary biologists to assume that various DNA proteins evolve at a fixed rate, a recent study blows a hole in this theory. The September 25 issue of the Proceedings of the National Academy of Sciences, geneticist Francisco Rodriguez-Trelles and colleagues at the University of California, Irvine, indicate the idea of a molecular clock may be hopelessly flawed. "It may be ripe for the pawnshop" say Menno Schilthuizen, writing in Science Now.
Calculating the different mutation rates for three well-known genes for 78 species, researchers found widely different mutation rates even for closely related species. "Molecular clocks are much more erratic than previously thought and practically useless to keep accurate evolutionary time," says Schilthuizen. The authors of the research conclude that the neutral theory of molecular evolution (predictable or constant rates of change) is flawed and that changes in the rate of variation are left to the vagaries of natural selection (randomness). With no evidence to confirm the neutral theory of molecular evolution, scientists say this amounts to a "denial of there being a molecular clock."
Phosphate - - - - Guanine Cytosine Adenine Thymine - - - - Sugar A DNA Nucleotide Sequence Positions of the middle four proteins differs DNA is made up of many subunits or strings of sequenced proteins strung between a sugar and a phosphate molecule (called a nucleotide). Think of a wash line in the back yard. There are two poles (the sugar and phosphate molecules) with four proteins (amino acids – guanine, cytosine, adenine, thymine) hanging on the wash line. There are many of these "wash lines" in one gene and over time some of the proteins hanging on the wash line change their positions. One protein may be substituted for another, which is called a mutation. Different species of life have some of the same genes and therefore the rate of change (number of protein substitutions) can be used to calibrate a DNA clock. Comparative studies of different proteins in various groups of organisms tend to show that the average number of amino-acid substitutions per site per year is typically around 10-9. Calculating backwards, scientists have attempted to use the DNA clock to determine when, let's say, chimpanzees and man diverged from the same genetic tree. There are a lot of assumptions here (even that there is a genetic tree at all) but the scientists believe humans and chimps split off from a common ancestor about 5.5 million years ago.
But the DNA clock is not so reliable. Paleontologists calculate the Cambrian explosion, the sudden appearance of a fossil record that is rich in almost every species of life, occurred about 540 million years ago. But DNA clock estimations come up with a date of 1 billion years ago for the Cambrian explosion. So there is an unexplainable 500-million year gap. Which provides the most accurate dating, the fossils or the genes?
The so-called neutral theory of evolution holds that DNA mutations (protein substitutions) accumulate at an approximately constant rate as long as the DNA retains its original functions. The differences between the sequences of the same DNA segment (or protein) in two species of life would then be proportional to the time the species diverged from a common ancestor. The undeniable problem is, different DNA protein sequences (or even different parts of the same gene) "evolve" or change at markedly different rates. For example, mutation rates in primates are slower than in rodents. This also assumes that all mutations move progressively rather than in reverse.
If what these researchers say is true, that the theory of a molecular clock is hopelessly flawed, scientists have some real reorganization on their hands. There are no less than 30 textbooks written on molecular evolution in the past decade and numerous PhDs awarded in this area of investigation. To date, no convincing evidence for a phylogeny tree has ever been produced. The evolutionary trees shown in biology textbooks are simply theory, not science. Genetics does not confirm its existence either, though it took scientists more than three decades to determine this. Few scientists are expected to abandon the theory of neutral molecular evolution anytime soon.
Sources:
Francisco Rodriguez-Trelles, Rosa Tarrio, Francisco J. Ayala, Proceedings National Academy of Sciences USA, Volume 98, pages 11405-10, September 25, 2001
Schilthuizen, M, Molecular Clock Not Exactly Swiss, Science Now, Sept. 28, 2001.
Dictionary of Biology, Oxford University Press, Market House Books, 2000. National Human Genome Research Institute
October 2, 2001
Bill Sardi is a journalist residing in Diamond Bar, California. His new book is Big God vs. Big Science (Here & Now Books, 107 pages)
The title is an outright lie. First, evolution in no way requires the existence of any molecular clock, and second, there are myriad ways in which genetic evidence does support evolution.
Chest thumpers from the caves--trees on a free ride in a govt. paid for bananna train---"schollarship" of the swamp-jungle!
only on the planet zandor...
all the article says is that the rate of change in a specie's DNA may not be as constant as was thought. Doesn't say anything about our ability to match a sample of DNA found at a crime scene to whoever left it ther.
Looks like the writer's 'molecular clock' is in need of repair as well.
It seems that Bill Sardi went to one of those schools where they don't expect students to know silly things like names and dates, but give them plenty of self-esteem.
Only the ideologues. Quotes from intelligent scientists didn't read like that:
"...an intelligible communication via radio signal from some distant galaxy would be widely hailed as evidence of an intelligent source. Why then doesn't the message sequence on the DNA molecule also constitute prima facie evidence for an intelligent source? After all, DNA information is not just analogous to a message sequence such as Morse code, it is such a message sequence." (pp. 211-212)
Charles B. Thaxton (Creationist)
Ph.D. Chemistry, Postdoctoral Fellow at Harvard,
Staff member of the Julian Center
The Mystery of Life's Origin:
Reassessing Current Theories
Philosophical Library, 1984
"At that moment, when the DNA/RNA system became understood, the debate between Evolutionists and Creationists should have come to a screeching halt
I.L. Cohen, Researcher and Mathematician
Member NY Academy of Sciences
Officer of the Archaeological Inst. of America
Darwin Was Wrong - A Study in Probabilities
New Research Publications, 1984, p. 4
Of course not.
Most scientists won't really look is the problem, IMHO.
They are simply out to prove their point, which is very unscientific research.
An intelligent design necessitates an Intelligent Creator. Take that to the bank.
Truth bump.
You know, these clowns have to rely on personal insult. Their theory is so weak. When are they going to admit the truth. Evolution is an atheistic religion (Buddhism is also an atheistic religion.) And universities should change the doctoral degrees of people like Physicist from Doctor of Philosophy to Doctor of Theology. In fact, people like Physicist, in their newly recognized role as priest, rather than scientist, should start wearing funny robes, and should learn some incantations.
You failed to demonstrate how this latest finding would invalidate the use of mitochondrial DNA to map genetic similarities amongst various species. But thank you for sharing your feelings.
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