THE ROCKEFELLER UNIVERSITY

pro bono humani generis
1230 YORK AVENUE - NEW YORK, NEW YORK 10021-6399

OFFICE OF THE PRESIDENT

, u/ L December 16, 1989

Dear Ron -- an

Since you abandoned molecular biology for the brain, we’ve not had too much occasion for
discourse, and have used none of it for some time -- though I have been pleased at the
evidence from time to time of your success in the field you did choose.

What brought you to mind once again was this enclosed article in Nature (11/24). I recall
we came pretty close to the notion that the "hybrids" had broken through a barrier to
heterologous recombination; though I’d make no claim that he could have had a precise
enzymatic mechanism in mind. It seems a reasonable bet, in retrospect, that some of the
hybrids were indeed mismatch-tolerant mutants.

I was led to run a citation index for the last couple of years; and I was startled to see how

often your B. globimar papers have been quoted (not to lose sight of your more recent. This
is all on a new toy, the SCI on a CD-ROM, which is a fabulously efficient way to recheck the

letters DLT,

So, by way of "hello, again", here is the printout for 1987-now. If you can use, and wish
to have the file on a floppy or over the net, just let me know.

all best wishes

Yours sincerely,

shua Lederberg

ae