Where did the 2.3 kb band go?

Michiaki Masuda masuda at fcs280b.ncifcrf.gov
Fri Apr 8 16:09:03 EST 1994

    I've been using GIBCO BRL's lambda DNA/HindIII molecular size marker.
Recently, I realized that the 2.3 kb band of the marker became fainter,
and now it's almost unvisible. If that happened to the 4.4 kb band,
I'd assume that it is due to the cos site annealing and heat it at 65 C.
However, as I understand it, lambda phage DNA 2.3 kb HindIII fragment 
wouldn't be involved in the cos site annealing. In fact, heating the
marker at 65 C for 5 min didn't bring my 2.3 kb back. If it were DNA
degradation, other fragments should be lost as well. However, other
bands are clearly visible.

    I've been using lambda/HindIII markers from different sources (including
home-made ones) for almost a decade, but this is my first experience in
losing the 2.3 kb band.

    I wonder if anyone here has a similar experience. Would anyone have
any possible idea to explain this apparently sequence-specific
degradation? Or have I just made a great discovery of the century?

Michiaki Masuda
Visiting Associate
Laboratory of Molecular Oncology
National Cancer Institute
Frederick, MD 21702-1021
E-mail: Masuda at ncifcrf.gov

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