Re: [MLUG - DISCUSSION] cloning

[Stephen Montgomery-Smith <EMAIL:PROTECTED>]

Christian M. Cepel wrote:

> Vern Green wrote:
>
> > I would argue that a clone would indeed not act the same. Most of what 
> > makes us who we are is through our experiences. We act the way we do 
> > based on external influence. My character is in no small part 
> > developed from interaction with my father, which no clone of me will 
> > have access to.
> >  
> > Even in terms of the way I look. A clone might resemble me in many 
> > ways, but there are no guarantees that certain genetic traits would 
> > crop up. For instance, I have a crooked little finger. I learned in 
> > biology (one of the only things I learned in biology) that this is a 
> > genetic trait, similar in nature to the "widow's peak". There is no 
> > guarantee that a clone of me would have that same trait. Some of the 
> > scientists on the list would correct me if I am wrong.

> If the crooked little finger is a phenotypic expression of a genotypic
> encoding, it would absolutely be present in your clone.  There is none
> of the random recombinant sampling you experience when the DNA encoded
> into the sperm or egg.  WYSIWYG.  In a clone, any phenotypic expression
> would be the exact same.

I think that just because there is a gene in your DNA doesn't 
necessarily means it doesn't get 'expressed.'  Every cell in your body 
has the same set of genes, but they all perform different functions. 
Thus by necessity there are complicated mechanisms which say which genes 
get expressed and which don't.  These mechanisms often are related to 
the environment, so for example, what part of the body they are in 
(which they can tell by which 'homeobox' proteins are present), or also 
to the internal state (i.e. a blood cell will split into two blood cells 
no matter where it is).

Thus even in a broader sense, certain genes might or might not be 
triggered by external events.  I am told that this is conjectured with 
Schizophrenia.  It is a genetic defect, but it is only expressed if the 
unborn baby gets a certain type of flu virus in the womb.  Once this has 
happened, the symptoms are bound to appear in the teens or early 
twenties.  But in of itself, the presence of the gene does not guarantee 
the person will get Schizophrenia.

I have read some about all this.  The mechanisms are many and varied, 
and many not all that well understood - all in all it is a very exciting 
and fast moving area of research - much is known, and yet much much more 
yet to be known.

Stephen

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