UNIVERSITY OF CAMBRIDGE   DEPARTMENT OF PHYSICS

  TELEPHONE
CAMBRIDGE 54481

CAVENDlSH LABORATORY
  FREE SCHOOL LANE
     CAMBRIDGE

MRC Unit

Dr. M. '$J, Nirenberg,
Department of Health, Educeation,
  and Yelfare,
Bethesda 14,
MD.,
U.S.A.

4th January, 1962.

Dear DrO Nirenberg,

  It was very kind of you to send me your two papers,
and I look forward very keenly to your next one0  I liked
the first paper very much, but I felt that perhaps Ochoa
had rushed you into publishing the second one in rather a
hurry,  We hear that Leon and Maxine are helping you pre-
pare the polymers,  I hope that this is true, and that all
is going well.  It must be maddening to have the whole world
jumping into one's problem.  I must confess that we are doing
a little on it ourselves,  in collaboration with Marianne0
Our results are broadly the same as everyone else's, except
that we get incorporation with 4 poly UC having a measured
U/C ratio of about 0.24.
amotig other things.    This incorporates a lot of proline,
             In our hands poly C doesn't appear to
work, but we think this is because it is double-stranded.
However, we haven't pursued this.  I should be surprised if
CCC is not proline, as you claimed in your PNaS footnote.

  I will certainly give a talk at NIH, bu-t I think it had
better be on the genetic work.  Ve can talk about the bio-
chemistry privately.

  I. have to be in Yashington for the Biophysics meeting,
and expect to be around till at least the evening of 20th
February.  Perhaps you could collate your invitation with
David Davies, who has suggested I give a general evening
lecture.  Let me know what you fix up between you.

  The English papers have made rather a fuss about our
Nature paper, which was published on Saturday, but as far as

2/....


UNIVERSITY OF CAMBRIDGE   DEPARTMENT OF PHYSICS

  +l-liLEPHONE
CAMBRIDOE 54481

CAVENDlSH LABORATORY
  FREE SCHOOL LANE
    CAMBRIDGE

Dr. I@. W. Nirenberg.
4th January, 1962.

-20

I have been able I have stressed that it is your discovery
which was the real break-through0

Looking forward greatly to seeing you in February.

Yours sincerely,

F. H. C. Crick