HARVARD SCHOOL OF PUBLIC HEALTH

 

Department of Cancer Biology

 

Dear ooh February 3, 1991

Just as our paper on the spontaneous reversion of
frameshifts was on the brink of going to press, Pat Foster and
I discovered (through a combination of unexpected results) that
most of the Lact revertants detected in the last set of
experiments in the paper (which used a strain bearing a +2
frameshift in the middie of lacZ) were probably due to
recombination between the test strain and the “scavenger” cells
(whose episome bears a lacZ with a deletion that does not extend
as far as the middle of the gene} and did not represent simple
back mutation of the frameshift.

Thanks to the kindness of the the editorial office of
Genetics, we have been able to pull back the paper, and so now
we will set about repeating the two experiments done with the
+2 frameshift strain in a way that precludes any interaction
with the scavenger cells.

As for the rest of the results (using a strain with
a +1 frameshift in lacI), they stand secure: the scavenger cells
bear a deletion of the region containing the frameshift, and we
know from other experiments that the presence of scavenger cells
is not adding to the number of Lact revertants. So the main
conclusion of our paper remains unchanged.

 
  

C Sasa \ clvalh Lele Wow we tJ how
7 Pegs ne

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