Dr. Donald Fredrickson 
September 13, 1978 
page -2- 
If unidirectional plasmid transfer had been accepted as an adequate 
criterion for inclusion on the Director's List, the strain would be auto- 
matically exempt. The reason for not accepting that criterion was that some 
doubts had been expressed as to whether unidirectional plasmid transfer auto- 
matically implied bidirectional transfer of chromosomal genes. However, in 
the present case, the ability to construct the desired recombinant is de facto 
evidence that it could arise by natural means. 
A specific proposal was submitted to RAC by Dr. A. D. Kaiser (Stanford Medical 
School) in which he proposed to splice an coli suppressor into an IE. coli 
transposon, then move the resulting combination into Myxococcus by PI trans- 
duction. This strategy will allow the isolation of suppressible mutants of 
myxococcus and its phages, which will greatly expedite genetic studies of 
development and motility in that organism. 
Sincerely yours. 
Allan Campbell 
Professor of Biology 
AC /an 
cc: John Spizizen 
Julian Davies 
Martin Dworkin 
David Dubnau 
Stanley Barban 
Jane Setlow 
[A-141] 
