The evolution of Cavalli-Sforza. Part I

Germ warfare was a priority for both Allied and Axis scientists. Was one of them a young L.L. Cavalli-Sforza?

With an academic life spanning almost half a century, L.L. Cavalli-Sforza has become perhaps the foremost authority on human population genetics.

He first entered this field in the early 1940s. As a medical student at the University of Pavia, he encountered Emilio Veratti, who lectured on Italian genetics, and Adriano Buzzati-Traverso, who specialized in fruit fly genetics. He went on to study the genetics of bacteria, specifically how to select strains that can better resist radiation and nitrogen mustard (mustard gas):

Starting in 1941, bacteria had become my major interest and in 1948 I gave a paper at the International Congress of Genetics in Stockholm on cross resistance to radiation and nitrogen mustard in E. coli based on work done earlier in Milan with Niccolo Visconti (Cavalli-Sforza 1992).

This account, written forty years after the facts, is consistent with a description he gave in 1950:

Nitrogen mustard resistance was found to be gradual or abrupt in increase in different experiments, only a moderate degree of resistance being acquired, which made a detailed analysis difficult. In E. coli K-12 nitrogen mustard resistance is not accompanied by higher resistance to radiations, as in the case of E. coli B. (Cavalli & Maccacaro 1950)

In the same article, he also described experiments to make E. coli more resistant to chloromycetin, an antibiotic. It is not clear where, when, or for whom this work was done, although some of this research could have been postwar (or early war, i.e., before the U.S. entry in Dec. 1941). The co-author, G.A. Maccacaro, had been supported by a grant from the Rockefeller Foundation, and the K-12 strain had been supplied by an American researcher.

In an earlier article, however, Cavalli-Sforza reported findings from another research project. These findings were the mean death times (i.e., time to death) of mice in response to progressively higher doses of anthrax and pneumococci (Cavalli & Magni 1947). This research was novel in that it measured time to death, as opposed to the percentage killed.

To learn more about this period of Cavalli-Sforza’s life, we can turn to his recent autobiography. Among other things, his research work took him to Germany:

I went to see him [Emilio Veratti] to ask him for advice about certain bacteriological research that I had conducted with Giovanni Magni, my college and faculty classmate. It had to do with a study on bacterial virulence using a mathematical method. Veratti told me that to his knowledge the only person who could help us was a German professor, Richard Prigge. We later discovered he was right.

[…] With Magni, in Como, we studied anthrax, which is still talked about today because it is one of the most fearsome bacteriological weapons

[…] it was not so difficult to measure bacterial virulence [in mice] and we continued our research because we really wished to study this mechanism with a view to creating possible vaccines.

At this point, the advice of Veratti, who had suggested that we try to obtain a scholarship to study at Frankfurt am Main with Prof. Prigge, the only European scientist who could understand the worth of our experiments, proved to be useful. We had the luck of getting a scholarship to spend the summer [of 1942] in Germany. (Cavalli-Sforza & Cavalli-Sforza 2008, pp. 31-34)

The autobiography mentions another stay in Germany, this time with the renowned geneticist Timofeeff-Ressovsky:

Buzzati asked us, Magni and me, to join him in Berlin, in August 1942, at the Berlin-Buch Kaiser-Wilhelm Institute of Genetics (now the Max-Planck Institute). It was a bit before our research stay in Frankfurt with Prigge.

At the time, the Institute was run by the famous Russian geneticist Nikolai Wladimirovich Timofeeff-Ressovsky, a man of an extraordinary personality, intelligent, likeable, and enthusiastic; in sum, very Russian.

[…] After my meeting with N.W. Timofeef, I decided that I would devote my career to genetics research. (Cavalli-Sforza & Cavalli-Sforza 2008, pp. 39)

One gets the impression that the meeting with Timoffeef in Berlin happened during a short stay, perhaps a single visit. Yet when Cavalli-Sforza dedicated his genetics textbook to Timoffeef in 1947, he called him “a friend and teacher, with the wishes that he will be able to continue his work” (Cavalli & Buzzati-Traverso 1947). These words suggest a longer working relationship.

Cavalli-Sforza’s autobiography provides the best account of his wartime research, but certain details contradict those in his earlier accounts. For one thing, the earlier ones (with one exception) have him studying E. coli, and not anthrax, although this contradiction may be more apparent than real. He could have been working with E. coli as a prelude to riskier work with anthrax. Alternatively, the E. coli work may have been postwar.

But the contradiction is more fundamental when it comes to his research aims. The earlier accounts have him seeking to create more resistant strains of bacteria, and not better vaccines. These two aims are contradictory because vaccines are normally made from weaker, not stronger strains. Perhaps he also wished to study drug resistance—a legitimate subject of medical enquiry. But why was he also interested in bacterial resistance to radiation and mustard gas?

This sounds more like germ warfare research. More precisely, he seemed to be working on ways to combine anthrax with chemical and radioactive agents, presumably as part of a single warhead.

We’ll probably never know the whole story. Perhaps even Cavalli-Sforza didn’t know. And does it matter? Neither side used germ warfare in WWII, out of fear that the other side would retaliate in kind. (Yes, our side had its own germ warfare program).

Still, it does matter. It certainly did to Cavalli-Sforza. He apparently dreaded having his wartime record brought up, and this dread would guide his behavior later in life ...

Note

During the war years and the immediate postwar era, Cavalli-Sforza published under the name of Cavalli. To date, I have been unable to locate his four wartime articles or even their titles.

References

Bonezzi, G, L.L. Cavalli, and G. Magni. (1943). Zentralbl Bakteriol, I Orig, 150, 17–25.

Cavalli, L. L., and G. Magni. (1947). Methods of analysing the virulence of bacteria and viruses for genetical purposes, Heredity, 1, 127–132; doi:10.1038/hdy.1947.8
http://www.nature.com/hdy/journal/v1/n1/abs/hdy19478a.html

Cavalli, L. L., and G. Magni. (1943). Zentralbl Bakteriol, I Orig, 150, 25–32.

Cavalli, L.L., and G. Magni. (1943). Zentralbl Bakteriol, I Orig, 150, 353–371.

Cavalli, L.L., and G. Magni. (1942). Boll d Soc Med Chir Pavia, 20, 609–624.

Cavalli, L.L. and G.A. Maccacaro (1950). Chloromycetin resistance in E. coli, a case of quantitative inheritance in bacteria, Nature, 4232, 991-992.

Cavalli, L.L. and A. Buzzati-Traverso (1947). Teoria dell'urto ed unità biologiche elementari, Milan, Longanesi.

Cavalli-Sforza (1992). Forty years ago in genetics: The unorthodox mating behavior of bacteria, in J.F. Crow and W.F. Dove (eds). Anecdotal, Historical and Critical Commentaries on Genetics, Genetics Society of America.http://profiles.nlm.nih.gov/BB/B/C/C/Z/_/bbbccz.ocr

Cavalli-Sforza, L.L. and F. Cavalli-Sforza (2008). La génétique des populations : histoire d'une découverte, Odile Jacob.