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                                   21 October 1976



Dr. F. M. 63. Crick, F.R.S.,
Tha Salk Institute,                                                                      

Pas% Office Bsx 18OEs,
San Dfego,
California 92112, U.S.A.



Dear Fr&Rcls *

   Thank you for eiI1 the new letters, ~~~ti~~l~r~y tbo correspondence
wi.th BE&.  P certainly is an excitiug tiw?. and I very much liks your
idea of ths supersolanafd.  I have called a ehrsmatin mgsetingg for tu.5              +.
Fridsy ,  at which Ashburner and   dney will be prasernt.  I have already
had a wcwd with S dney,  and he
       3             ERks your point (in your Jotter of
14 October) about translaoation  fe a good one.  I wfll write again
after th9 mm3ting at whfch the gcmatic ~rn~l~c~%~~~g will have been
d~S6~SS~d.

   OR the supersol~~sid itself, I havs novi fournd my notes on the
E.M. ~~%0%~n~ in Jemsal3m,  and Bans Ris def ni%ely said that mitotic
ch~omosmies were3 fcrlpnnefd by folding the 250   ffbre into OR.63 of dfmster
about 108Q -  0 w. ~iCira>wew%r hs did not ~r~s%~t amy ~~~t~~ss (his
slides were lost when his baggage wcw srtalen at Par%s Airport!) but
I suspect they would splow tha SL~MQ sort af murky pfct~es 88 k&km@,
and the, ddea of coiling into a thfcker fibre is just a @neral oue.
I doubt- i-f hs has any shard evfdencs, but he may hawe borne estimates
of diams%srs from seations.  This value -r;ay be a tsicky one since
I would Lmagirae that it could shange fairly Qasfly if the coils of
tka aupsraolsnoid were not held by ties.         dary  idaa of tha
ties bafng preserved fs 8 very xlsat cm%, but 3 wonder if it isn't r;all
ov%rs~mpI~f~ed.  Sid~cey ,thaught it urtlikely, but I do gee the point of
the possible correlation between the smorllnsss of DrssopfiJtla mrEstaphass
chromosome and that smaller size of the genes.

   I have been. looking at g~-~pere on ths elactlron microscopy af
sectioned m.ftotfu chromubaomes asld there is just ILO trace of a hollow
cexltre .  There Pilre many examplwt, but I enclose a reprint of ai old
psper of Hugh's, SBCB flgura 14,  Richard Skaer has a380 brought in Born&
much more rscent photographs,  and what one 8888 ia transverss*section
m-63 fairly dense bsdias about a micron across.  Even allowing for the
posalble double helical coilfng at the next level, I think 8 hollow                  
tube would have bmm svfdont ~VMJ. if it had bean canafderabPy flgsttened.     "     '

Perhaps the lumen is filled wvfth other proteins and possibly some
lot?ser DNA.  This last notion is distasteful as I thzink you are right
that the metrjcphaae chromosome should have a compact, and therefor%
rsgular ,  structuru3.


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'Ibours ever,

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