This is one short repeat. In humans it varies from 53 copies of the
short sequence that is repeated to 160 copies. The length of the repeat
seems to be associated with telomerase expression. The 50% of the
genome is talking about VNTRs (variable nucleotide repeats) like this
satellite sequence, and most of the heterochromatin is made is made up
of short repetitive sequences like this that do not code for a protein.
The VNTRs are dispersed all over the genome and we used to use them
for genetic mapping. Look up microsatellite markers. Most of them
don't seem to have any function that we could figure out, but some of
them were associated with genetic disease if they were found inside a
coding sequence because they are highly variable (mutation rate of E-5
or more).
What is also strange about you putting this up is that Telomerase is
used to maintain a short VNTR on the ends of chromosomes. The longer
the telomeres the longer the life of the cell is a general observation.
What does this tell you about any stupid notions that you have about
junk DNA?
Ron Okimoto