Glenn writes:
>Walter, I think you err in your number of 50 divisions prior to the formation
>of the next sperm cells. The human brain has 10^12 cells, (Scott Gilbert,
>Developmental Biology (Sunderland: Sinauer, 1991), p. 172) The brain
>represents about 1/10 of the human body so, we can expect that the body has
>no more than 10^13 cells in it. If what you say is true then starting with a
>single cell and dividing it 50 times, gives 2^50= 10^15 or 100 times the
>number of cells I have in my body! So, before reaching sexual maturity, a
>child must grow to be 10 times my size? What a football player!
After fertilization there are many cell divisions before the germ cells are
segregated and isolated from the somatic cells. These germ cells eventually
produce the sperm and egg. The germ cells represent the germline of
inheritance, and they go through about 50 generations of duplication for
each "generation" of the organism. In man "the number of cell divisions
along the germ line from fertilized egg to a gamete is roughly 50" (Motoo
Kimura, 1968, _Nature_, Vol. 217, p 626). The cell divisions in the rest of
the body (i.e. the brain) are irrelevant.
>If I recall your argument about Haldane's Dilemma (and admittedly I am rusty
>with that argument) you say that evolution can not occur because in 1500
>generations enough mutations would load the organism to destroy it. Wouldn't
>your 50 additional steps make the continued survival of the human race at
>risk now?
That doesn't represent my argument. In my chapter on Haldane's Dilemma I
discuss the issue of harmful mutation. By using evolutionists' figures for
mutation rate (figures which already correctly incorporate the above factor
of 50), and the standard model of evolutionary genetics, I show that many
species with low reproduction (such as mammals and man) are close to, if not
within, error catastrophe, where genetic deterioration occurs generation to
generation. I did not put a time limit on the process. I didn't say
anything about 1500 generations.
>Thirdly, AND MOST IMPORTANTLY, the rates of mutation are not based upon that
>observed by each cell division. We can't tell if a human cell has a mutant
>form for two heads by looking at the cell. We can only tell when the child
>is developed enough to see that there are two heads. So the rates are based
>upon a PER GENERATION risk of mutation, not a PER CELL DIVISION rate!
Glenn's original post spoke of DNA mutation rate PER DUPLICATION, not per
generation, and he quoted a reference that used that language.
>Thus if you want to use the correct number then you need to divide the
>10^--7 by 50 (I believe, it is quite late and I fear a math error) to
arrive at the
>correct rate per CELL DIVISION rather than the rate PER GENERATION.
In effect, Glenn is saying he originally meant his numbers to represent the
'per generation' mutation rate. That doesn't change the response I made in
my original post, as I had already made an assumption in Glenn's favor by
setting aside the factor of 50 and leaving it out of the calculations.
>You missed the point entirely. I asked how the number of alleles arose in
>the time allotted by the YEC's
Using Glenn's figures, and assuming a population size of one million, my
previous post showed:
1) EACH progeny receives about 700 NEW mutations.
2) The population as a whole receives 700 million NEW mutations EACH
GENERATION.
3) A 1000 unit gene receives 200 NEW mutations (or new alleles) EACH
GENERATION -- and Glenn only asked for 59 in 200 generations. One
generation is enough to accomplish what Glenn said couldn't be accomplished
in 200 generations.
So in this post Glenn has begun altering his argument. Like this:
>Now, I agree that you can get a mutation in this
>gene, but unless I am mistaken, most alleles are quite different in their
>sequence from one another. If all alleles were only 10 substitutions
>different from each other, then you might have a case, but if the allelic
>sequences are substantially different, then there has not been enough time to
>generate enough substitutions in this given 1000 unit long sequence.
That is a different argument than he made previously. Now he is focusing on
the *number* of mutations within a given allele, and he is focusing on
substitutions. Neither of those matters was in his previous argument. The
issue was not substitutions, instead the issue was the *presence* of 59
versions a given gene (known as alleles).
Though Glenn is trying to shift his argument to new matters (which is okay
by me), he has not actually made that new argument here.
>Why have we not seen more change in them [cats], or why have we
>not seen the destruction which Walter would predict?
We have seen "change" in organisms (including cats). Glenn asks why we have
not seen the amount of "destruction which Walter would predict." That's
quite a switch for Glenn. First he argued that organisms cannot supply
enough genetic change rapidly enough, then when I showed him, he turns
around and argues that it's too rapid!
He then suggests that to bring the situation in line with reality the
mutation rate would have to be slower:
>Maybe because the mutation rate is slower than what I estimated,
>which exasperates the problems for the YEC's.
Glenn has not shown any problem with the rapid production of genetic
variation. On the contrary, he implied that a lower mutation would be
sufficient. So he then took a double step and suggested a MUCH lower
mutation rate -- in an attempt to create ("exasperate") the problem for YEC's.
Glenn forgets that a much lower mutation rate aggravates certain problems
for evolutionists. The maximum plausible rates of beneficial substitution
and neutral substitution are already too slow for evolutionists (see my book
or my posts of several months ago on Haldane' s Dilemma). Those rates are
tied to, and limited by, the mutation rate. A lower mutation rate slows
things down and makes those problems worse. So when Glenn suggests a much
lower mutation rate, he is really playing with a two edged sword. I urge
caution.
******
>Walter wrote:
>>Let me clarify Glenn's statement for our readers. A typical gene is 1000
>nucleotides in length. With a mutation rate of one in 1E7, the typical gene
>would experience one mutation in 10,000 generations. <<
>
>We agree on something. If the YEC view of the flood is correct, then there
>have not even been 10000 generations since the flood. If there was a flood,
>then it must have occurred a long, LONG time ago.
Glenn misunderstood. With his mutation rate of one in 1E7, the typical gene
-- ONE instance of one gene -- would experience one mutation in 10,000
generations. In other words, start out with one copy of the gene, replicate
it once each generation through 10,000 generations. You now have one copy
of the gene, it is the 10,000th grand-daughter of the original, and you'd
expect it to contain one mutation. Now take 10000 copies of the gene
through ONE generation -- you'd expect one mutation within the group. Now,
in a population of one million diploids, there are two million copies of the
gene, so you'd expect 200 new mutations in ONE generation. (2 million /
10000 = 200). In 200 generations you'd expect 40000 new mutations.
******
>Walter, if I am not mistaken, you have really messed this one up. Each of
>the million people have a history of 200 generations from Noah who represents
>the genetic bottleneck.. That is all! I can not pass a mutation to you
>and this is what your math wants me to believe. Your population number is
>being used as if I make a copy of my genes, give them to you and you copy
>them and give them to your neighbor who continues the process. After my
>genes have been copied and passed through the entire population of Dallas,
>you would be correct, there would be 40,000 mutations to that gene. But this
>is NOT AT ALL how life operates!!!!! If it is, my biology teachers failed me
>miserably..
Glenn is mistaken about my argument, which does not require that neighbors
pass their genes around. In fact, my argument holds even for an asexual
population, where no genes whatever are passed between individuals. My
argument is exceedingly simple. Start with 2 million copies of a gene,
replicate those through 200 generations. You would expect 40000 mutations
to that gene.
Perhaps Glenn might complain that I started with a population size of one
million. But the human population has been that large for virtually all (if
not all) of 200 generations, and typically has been much greater.
I don't want this to turn into a debate about rates of population growth
back several thousand years ago. So let me add a modern perspective that is
irrefutable. Take a population of one billion people (that's 2 billion
copies of a given gene). In merely THREE generations that gene would
receive: 2 billion x 3 / 10000 = 600,000 new mutations. Glenn only asked
for 59! There is nothing historically to quibble with here, as this
argument used known sizes of modern populations. When Glenn asks for
"genetic variation", I can supply it in abundance.
Walter ReMine
P.O. Box 28006 NEW ADDRESS
Saint Paul, MN 55128