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ISTITUTO DI GENETICA 27th February, 1970
UNIVERSITA DI PAVIA
VIA SANT’EPIFANIO, 14
27100 PAVIA

Prof. Joshua Lederberg
Genetics Department
Stanford University

School of Medicine

Falo Alto, California 94305
U.S.A.

Dear Joshua,

I have read the paper by Halpern and others on the
utilization of mass spectrometry for the assay of amino-
acids in plasma. It occurs to me that an extension of the
method to cover all aminoacids in normal plasma might have
some interesting applications. Here is one.

There is some direct evidence that Pygmies are more
susceptible to Kwashiorkor when exposed to a protein low diet.
We have data showing that healthy Pygmy adults have concen-
tratiorg of aminoacids in plasma resembling those of Kwashiorkor
- sort of midway with respect to normals. The attractive hy-
pothesis can be made, that Pygmies, never having been exposed
to selection for low-protein diets, (as they never were entirely
in an agricultural economy) have not adapted to it. The adap-
tation of those who have had several thousands of years of
agriculture, as practically all other Africans have, may be
genetic but, in view of the relatively short time elapsed,
it may be that selection is still incomplete and many indi-
viduals may still carry the original lack of resistance to
a low-protein diet. These may be the people especially prone
to Kwashiorkor.

Telefoni: 23.029; 29.038 - Indirizzo telegrafico: Istgenetica - Pavia

One way to test this would be to investigate a number
of twin pairs (in Africa) for their aminoacid patterns,possibly
before and after weaning. Weaning marks the passage from high
to low protein diet,and might be accompanied by signs of Kwa-
shiorkor. There exists in Nigeria a number of tested twin pairs
and more could be looked for. I would be prepared to go there
to organize this, but present methods of aminoacid assay demand
a large amount of plasma (10-15 ml) which is prohibitive for
small children. Adult twins are much rarer, because of the high
mortality, difficult to find because of lack of demographic reg-
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istration, and less interesting for the purpose. Thus, a method of
aminoacid assay on small amounts of plasma would be ideal,especiall
as it seems possible to read the results on 50-100 lambdas,which
can be obtained by fingerprick techniques.

Another item. Dr. Vittorio Sgaramella, a chemist from Pa-
via, has worked with Khorana for a couple of years and is still
there. He was invited by Khorana to follow him at Boston (with
a Salary of 12,000 or nore He would rather spend a year or so
at Stanford. His wife is a capable biometrician with excellent
practice of computer work and has collaborated with me in the
past for a long time. Are you interested in having them in
Stanford? He might be very suitable for the directed transfor-
mation work you have in mind. I would appreciate an early answer,
as he asked my advice.

I have been interested by the idea of the doctorate of envi-
ronmental health Unquestionally mass spectrometry might be quite
useful to detect small amounts of extraneous substances. Many
possibilities come to the mind, but undoubtedly blind or semiblind
surveys in highly polluted environments might be the simplest.

I am just back from Africa where I collected blood samples
in Cameroun and Ethiopia. I have mt John and Mimi Summerskill
and they were extremely helpful. But there is hardly a ‘trace of
Pygmies in Ethiopia.

Who will be the new Dean? Has any progress been made?

Yours,

Cree