In his letter Donohue recited his contention that Fourier analysis of recent X-ray diffraction data did not conclusively prove
the validity of Watson's and Crick's model of base-pairing in DNA. (Fourier analysis is a mathematical technique used
to calculate the periodic functions that arise in situations of cylindrical symmetry, such as in fiber crystals of DNA.) Instead,
Donohue claimed that the data was compatible with alternative base-pairings as well. Donohue dismissed biochemical evidence
for the Watson-Crick model of DNA, for instance evidence for the antiparallel direction of the two strands, as irrelevant
to his argument, which he claimed was based on crystallography, not biochemistry.
Crick did not in fact publish the "considered article" he mentioned in Donohue's letter. However, in a retrospective,
"The Double Helix: A Personal View," published in the April 26, 1974, issue of Nature (vol. 248, p.768), Crick summarized
that Donohue, "whose advice was crucial to our understanding of base pairing, was a persistent critic of the validity
of the later X-ray work, but in recent years he had carried it too far . . ."
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1970-08-10 (August 10, 1970)
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Medical Subject Headings (MeSH):
Embryology and the Organization of DNA in Higher Organisms, 1966-1976
Letter from Francis Crick to Jerry Donohue (August 3, 1970)
The Double Helix: A Personal View (April 26, 1974)
This is a combined reply to your letters of July 15(I) and August 3(II). I was in the process of finishing my comments on
(I), when (II) arrived.
I am not surprised that you were not surprised (II) that I felt I had to reply to Nature's remarks. Not Nature, actually,
but some masked reporter. What a stomach-centered creature, with his custard pie and hot potato! He seems to have a gustatory
hang-up, which perhaps compensates for his ignorance of diffraction, among other things.
I gather from (II) that Nature has agreed to publish a considered article by you, which is certainly preferable to a hasty
letter. If this is to contain the points at issue as you see them, i.e., that non-crystallographic dyads cause numerous reflections
to be effectively centric and that in centric structures my arguments have much less force, it would be only correct if the
same issue contained my point of view. Inasmuch as I am in no position to ring up the editor, as you have done, to make the
appropriate arrangements, why don't you explain the above to him? I just happen to have a manuscript on this subject
which constituted the first half of my first paper to Science, but which was scissored by the referees, who wanted the emphasis
on DNA, and not Fourier analysis, contrary to my original intention. It wouldn't take too much trouble to make it suitable
for a short Nature article to accompany yours.
However, I see no reason why you should quote my opinion in your paper. I would say that my opinion rightly belongs in a
paper authored by me, while your papers should contain your own conclusions, based on your experience and knowledge of the
To return to (I), most of it is really not concerned with Fourier analysis, and is thus not germane to what I have been talking
about. What Khorana did, and what the evidence is for how the chains run, etc., has nothing whatever to do with the calculation
of rho (xyz) and why that calculation, in this case, doesn't prove anything.
It is interesting that you have established that I do not have an adequate grasp of helical diffraction theory. You are not
aware that there is no such thing as helical diffraction theory. This "theory" doesn't tell us one whit more
than the expression [scientific formula] (hxi + kyi + lzi), which has been known for quite some time. The "theory"
merely provided a short-cut, in precisely the same way Knott's molecular structure factor method did, but no one talks
about molecular structure factor theory.
Finally, I see no reason for you to persuade the King's group to make available to me data which they should have published
in the first place. It amazes me that some people consider their structures "generally accepted". As my second mentor
in crystallography, J. H. Sturdivat, often said, "publish your data, for without them your structures can only be accepted
on faith, which has no place in science". So much for dogma, which hasn't been doing so well lately.