At 01:41 PM 10/6/01 -0400, John K Clark wrote:
>In the Oct. 5 issue of the journal Cell there is a report that the negative
>effects of short telomeres are not a function of average length as had
>been thought but a function of the shortest telomere in a cell.
Actually, I think this has been taken for granted for a while. It seems to
me to correspond interestingly with this earlier announcement:
June 15, 2001; University of Texas Southwestern Medical Center; Dallas, TX
-- A discovery by UT Southwestern Medical Center at Dallas scientists that
genes near human telomeres can be silenced may help explain how and why
humans age. [...]Dr. Jerry Shay and Dr. Woodring Wright, UT Southwestern
professors of cell biology, report in today's issue of Science that human
cells can exhibit Telomere Position Effect (TPE), a mechanism by which
genes near telomeres can be turned off, and that the strength of gene
silencing is proportional to the length of nearby telomeres.
So the shortest telomere of 92 in a nucleus is the one that will first mung
its adjacent codons; if these are crucial, the cell is in trouble.
On the other hand, I gather that the most crucial genes seem to be
preferentially located near the middle of DNA strands.
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