> It's real BASIC, your reprodutive organs must foster the
>mutations(ie.. sperm development between your legs) or the mutations must
>occur during conception. It's that simple. Biology 101.
It is more correct to say that mutation needs to occur in the germ cells in
order to be passed along to the progeny. The reproductive organs, to my
knowledge, do not "foster" mutation.
> So reguardless of external 'pressures' they mean nothing in the
>context of DNA mutation. So even if a mutation was made that favored a
>certain species to survive(which has never been observed) then this code is
>a candidate for the same random genetic mutations that got it there no
>matter how usefull the new triat was to the animal.
There are plenty of examples of simple mutations that affect survivability
of individuals in a species. Examples include the sickle cell hemoglobin
gene, and the major histocompatibility locus.
On a more basic point, John fails to distinguish between genetic mutation
and phenotypic polymorphism. He is correct in that selection does not work
at the genetic level, but differential survival and reproduction certainly
do affect the frequency with which different alleles (which can arise by
mutation) are found in the population
> Asking me to give a reference to how many mutations are required
>for an eye is really funny. You would be an idiot in the scientific
>community if you published a paper on how many genetic mutations are
>required to code for an eye. First of all the question makes no sense. Do
>you think that the DNA coding for the development of an eye is just some
>simple little code that is only in one location with no interruptions in
>the code. Do you think anyone knows the code for all of the genetic
>information behind it's development? If you were to answer this question
>you would need a starting point. As you probably do not know several
>codons may code for the same amino acid. So it makes a big difference as
>to where you start. Lastly, I feel really stupid answering this question
>since the random creation of an eye from any sequence of DNA could and
>would never happen. When given the fact that each succesive generation
>would expose the same genetic code to the same mutation it's even more
>ludicrous.
. The fact that the mutated gene can further mutate is not necessarily
important in considering whether the new allele can be fixed in the genome
of the population.
> I really think that you need to take a serious look at a biochem
>book. There you will find out that everything isn't as simple as it may
>sound.
> Am I sure that all of the intermediate steps are random? Did I
>miss something? It's all random mutations right?
> ACHALLENGE TO EVERYONE: IN LIGHT OF PIMS COMMENT:
>
>pim: Mutations are not limited to duplication of genetic material.
>
> Give me an example of genetic mutations thats will effect the next
>generation that do not include mutations that occur in the reproductive
>organs or during conception.
Randomness of mutation does not mean that evolution is random. The fact
that only certain newly formed alleles will be successively passed on to
subsequent generations means that the end result of the process is not
random. An analogy I used earlier is this: While the generation of numbers
for the lottery may be a random process, the end result of that process is
not random if someone stands by and selects only those numbers on his ticket.
Another problem with John's posts is that he seems to only consider point
mutations. Mutation can occur in which whole sequences of DNA are changed.
Also, mutations in different genes do not have equal phenotypic effects.
Thus, messing with only one or a few Hox genes can cause major disruptions
of body organization. Other genes that encode transcription factors can
regulate expression of numerous other genes.
Steve
_________________________________________________________
Steven S. Clark, Ph.D . Phone: 608/263-9137
Associate Professor FAX: 608/263-4226
Dept. of Human Oncology and Email: ssclark@facstaff.wisc.edu
UW Comprehensive Cancer Center
CSC K4-432
600 Highland Ave.
Madison, WI 53792
"It is the glory of God to conceal a matter, but the glory of kings to
search out a matter." Proverbs
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