Ruud Broens a écrit :
"Ruud Broens" wrote in message
...
:
: "Lionel" wrote in message
: ...
: : Well, the problem is, a change in the biological entity is coded in the
: : DNA, so a mechanism of environment - to - change in genetic code
: : with -better than random- good environmental fit characteristics...
: :
: : I guess you mean : is coded by the DNA in the chromosomes.
: :
: : What do we know about all the "useless" coded informations ?
: : Could we imagine that it can be quickly (re)activated in case of brutal
: : changes ?
:
: The process of celldivision in the so-called eukaryot celltype has a
: remarkable
: simularity between all sorts of species. This has led to the conclusion,
that
: this mechanism has remained virtually unchanged for at least a billion
years!
: Mutation of the genetic code takes place all the time, under various
: influences
: from both within and external to the biological entity. For certain 'core'
: mechanisms, such as division, there are very effective corrective
mechanisms.
: Just as you will find ice in a glass of hot water being present
: in a perfectly healthy body, cancercells are present - luckily, the
: 'countermeasure department' is quite efficient :-)
:
: Rudy

The description of the internal workings of such a eukaryot cell easily
matches the size of the printed phone-directory for New York,
so let's not pursue *that* further :-))
But basically, you have socalled introns, then the sequential code that
is transcripted, then exons. The transcripted codesegment is transported
to the factory (by RNA), as blueprint for some protein. One of the mutation
factors are retrovirii, through reverse-transcription of their RNA, causing
the insertion of new code in the DNA. A lot of the unused parts in the
code can be ascribed to retroviral mutation. Dystrofine, for example,
has over 2 million base-pairs, but only rougly 10000 are represented in
the mRNA to code for it.


Go ahead don't wait...
I will join you on the top as soon as they will have installed a ladder
for me. :-)