Etha,
It sounds like you're describing telomeres. Eukaryotic chromosomes are
capped by repeated sequences that protect the ends of the chromosomes from
enviromental damage. These repeated sequences are specific for each
individual. These repeating sequences are added by an enzyme called
telomerase, after DNA replication.
Part of the telomerase enzyme is an RNA component that acts as a primer
for the telomere repeat sequences. Teleomerase activity and teleomere
length decrease with age. Very short telomeres result in genetic
instablity and/or cell death.
Two articles recently appeared in Science. Try reading those. If you
need more information look at the article references.
Science 269:1236-1241 and 269:1267-1272
Happy Reading !!!
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Laura Custer
Dept. of Chemistry
The American University
Washington, D.C.
Lcuster at aol.com
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