Dr. E. L. ;"Ptu,
Dept. Blologgr,
Stanford Unbmrsity,
  California.

October 3,1950.

Dear Ed:

I"   EM38r and I are both very sorry that wu did not have an opportunity      I
to vi&, dth you a&n dblr3q the ~ui?plbbr~ but our few weeks in Bsrlsdrsy
prwed to ba ail tw abort to do aLl the things that we had hoped. We ii
reached Berkeley aeve~al day8 before the beginning of the second summr  'I
soseion, which gave us en opportunitgr to see amMing of northern hl.ifor-
nia. +~eviaitedDohzh+m&cy athi8 9-r &a~n~~thQT (via aonbway
lp0untai.n road in and out of Yosea&te), ;md thsn drove northwards to Lasmn
Park, which we greatly enjoyed for a couple of days. irl, returned to Berkelq
da ~I!Awska, the Badwoud kugfiRw, and Napa Halley. The oouree itself was
tiaratdy suc0emful8 at least the atadents rsiatsed to bsliwe everything
that I tried to M.l tham. I managed to do a vt~y Uttla rsseamh with
Stzmier on W affects of adaptation in &1m2dosonas. As one tight expeot
UV &rongly 5nhibfts adaptation, butnottha adaptud emyms. 'fhe 2nb1bit2.m
cm be photo-revsrsad, which mgpsts that phot'oreactTmtion is not the
interruption of a process leading to killing, but an actual *mversal of'
the photxmbeurioally teriaincll event, There ia not a great Oeal of rliffsrmccl
between t&map@ notion, but 1"JovicPk and %U.ard had besn thinking aora or lsss
in terms of a po%uon, whiah could be destroyed by light before it had rsaoted
with the cell constituantsr. The greatest use of thse findings mq+ be a~ a
better mans of distinguishifls adaptation th& by slight differences in
tha shapes of curves of 0 tiras. As I had tmticipate;d, it tlrrris out that
unadapted cells also co tlaiill wall ammnte ( a few $1 of the, oxidative
enzyme usuay$ ragaxded as adaptive.

The main point of this latter is to ask you about the program3 of thd~
orgmisation of the &mrospora mp, and to ask whether you would be k&d
enough to sand a fm atocks. Jams Crow and his atudsnt, Jam Pierlo, have
now gone through most of the praliminariss, md would Like to &m-t buXld3.q
up .mltiple mrkm stocka for cromover etmiies. From what I kna~, X thought
that the follov&g aarhm would be mst approprtite (on the sex chromomm)t


low- A7313
A/a
lyre or citr (stock R??)
csntromre
ad-p   35m3
mdh 35809
albino 15300
40    4545.

It w3J.l probably take rpeveral montha at learrt to build up the stocks, but
by doing them in blooks, md building two stmks in alternation it should
not be imposeible. We would aleo like to use a centromre maker for another
crhroa~osm, as a aheuk dn slippager i.e ., an aamu showing apparent rouond~
division segregation for the seaond csntroaera rmrker would be treated with
auapicion as a possible slippage of nuulei 11 and III after lpaioeir. I don%
have enough information to know what beat to use8 but thought at least to
try 51602 (B2temp). Would k~ you send this alm, if not mggestions on aumeW,ng
better to use?

Jim and I will very muoh appreciats any help you can giva us, and we will
u4WAnl.y keap you informed.

%, Columbue mM.ngs were intereating, but exhaueting. Conspiououely
good papers- Stadlar,DawUngton (the davllitmlf), and Ephrussi. Baadls
gave a rather surpr&&.ng talks he diaawasd the historiaal orix& af the
~~one-to-onell theory, and referred repeatedly to the one gene-one function d t)
hypOthOl!Ji~.

Latarjst wrote that he is on the hunt for possible traces in Paris of
coli Cl and C2, but refused to offer anp emouragement. "Ine Ghrussis null be
here in a day or two, uld I'll ask them aa w&L& - but they will tioubtadly
be hcxd.ng mstwrd theiris(slvcs.

Enough for nw-