Roslin sheep/genetics/aging questions

Katharine Lindner katel at
Thu Mar 6 00:20:30 EST 1997

Hang-Jun Chang <iam at> writes:

>Kevin Paul Grant wrote:
>>   Has "naked" (completely lacking in any covering molecules)
>>   DNA from a person ever been checked to see if it is the DNA
>>   itself that accumulates age-related damage?  Or is it possible
>>   that it is the stuff that covers the various genes that gets
>>   damaged and it is the symptoms of *this* damage that are at
>>   least partially responsible for aging?
>> Perhaps the DNA in sex cells (as they exist in normal fertilization)
>> is completely "uncovered" and some part of the cloning (or fetal
>> development) process can completely "uncover" covered DNA, removing
>> the damaged covering material and thus allowing "adult" DNA to be
>> used for cloning purposes without resulting in a damaged end-product.

>What a great idea it is! 
>Kevin's idea can be summaried as follows:
>The cause of aging is in the altered expression of genes like a 
>developmental process, rather than in accumulated damages to genes 
>themselves. Should a certain damage be involved in the aging process, it 
>may be in the molecules to regulate the gene expression.
>Thus, Aging may occurs as a result of altered expressions of genes 
>by such accumulated damages.

>I want to suggest that DNA methylation holds some answers to your
>Although I don't know much about it, as far as I know, DNA methylation
>patterns change as a cell differentiates, or ages.
>Perhaps DNA methylation appeares to be involved in transcription 
>regulation. I remember the journal Cell has several good reviews on it.
>I hope that this discussion goes on.
>Is there anyboy to comment it? I am really excited by this great post.

  Another possibility is that DNA in some cells is healthy and damaged
in others.  With a full organism the damage is averaged, but maybe in a
single cell its likely to be either dead or reasonably healthy.

  Yet another speculation.


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