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Crodowaldo Pavan

Reminiscences from the time of the Drosophilae

In honor of Crodowaldo Pavan, now deceased

Dreyfus, Chana, Dobzhansky, Martha Wedel, Antonio Cordeiro (seated), Hans Burla and Antonio Cavalcanti (standing): a time of great enthusiasm

Hans Burla/Comissão Memória IB-USP CollectionDreyfus, Chana, Dobzhansky, Martha Wedel, Antonio Cordeiro (seated), Hans Burla and Antonio Cavalcanti (standing): a time of great enthusiasm Hans Burla/Comissão Memória IB-USP Collection

In the history of Brazilian science to date, I think no researcher has had a curriculum so rich in achievement, with such success, as Crodowaldo Pavan.

He was especially fortunate in his professional life. He had, let us say, three top-notch guardian angels, who always guided and helped him greatly. This does not mean, however, that Pavan did not work extremely hard or did not dedicate himself entirely to his professional life in order to reach everything that he achieved. These angels were André Dreyfus, who provided him with guidance in the early days of his career, Harry Miller Jr., who, for 20 years, provided financial support for his research, and Theodosius Dobzhansky, his second guidance counselor and collaborator until 1956.

André Dreyfus, a full professor at the Biology Department of the Natural History course at the School of Philosophy, Science and Literature at the University of São Paulo, was a great intellectual. Originally from the state of Rio Grande do Sul, he studied medicine in Rio de Janeiro. There is a story according to which, in order to make a living, Dreyfus offered a histology course that was so good and renowned that the medical school professors themselves used to attend it. He became very famous and his notoriety soon extended beyond the city of Rio de Janeiro. He was considered an excellent teacher and, furthermore, was a man who kept himself always up to date, closely monitoring scientific development, especially in the biological areas. As soon as he graduated, he was invited to teach at the Paulista Medical School. He was one of the few Brazilians, back then, to be a full professor at USP’s then newly created School of Philosophy. He was in charge, specifically, of general biology, which comprised the teaching of genetics and evolution.

It was Dreyfus who advised the young Pavan to join the USP natural history course, during a fortuitous meeting at the end of a conference delivered by the former at the amphitheatre of the Municipal Library in São Paulo. And this was exactly what Pavan did: he gave up the notion of entering the Polytechnic engineering school in favor of studying natural history. He graduated in this field in 1941, with both teaching and bachelor qualifications.

At that time, Pavan had already become part of the Biology Department, having first held the position of biology instructor and later, after he graduated, of third assistant. He promptly started working on his doctorate under Dreyfus.

In 1942, Harry Miller Jr., the representative of the Rockefeller foundation for South America, sought out Dreyfus. With the advent of World War II, which began in 1939, the countries that had been getting financial aid from the foundation became unable to continue to pursue their research. Therefore, the foundation had decided to start investing in South America. Miller wanted to know whether Dreyfus might be interested in getting aid, perhaps through a grant to study further in the USA. Pavan, who accompanied Dreyfus to this meeting, was most enthusiastic about this opportunity to get financial aid from the Rockefeller Foundation. The subject was left to be decided at a subsequent meeting. Dreyfus, however, was adamant about not leaving Brazil and chose to have a foreign professor visit the country, which would be far more productive. After a long discussion, Miller agreed, as Pavan tells us very clearly in a rich and most interesting interview published in 2002 in the book 50 anos de CNPq [50 years of the CNPq], as retold by its presidents.

Miller then undertook to suggest the name of the professor who might be invited to work at the school of Biology: “I shall talk to professor Theodosius Dobzhansky!.”

The latter was at the height of his career, a demigod. The first edition of his book Genetics and the origin of the species, published by the Columbia University Press in 1937, was then reissued in 1939; a second edition was released in 1941 and was reissued three times (twice in 1947 and once in 1949). It was a major success. Moreover, Dobzhansky was one of the main researchers to introduce the drosophila as experimental research material for the study of the evolution and genetics of populations. It was to become highly fashionable, being adopted in all the main research centers of the world. He was at his apex and the leader of his field.

Miller persuaded Dobzhansky to amend his schedule and accept the invitation to visit Brazil. The professor, however, set one condition: he wanted to collect samples in the Amazon Region. Thus, in 1943, he came to the General Biology Department, which was housed at Alameda Glete.

Pavan was charged with accompanying the illustrious visitor on his travels around the North of the country. This proved to be an excellent opportunity for the establishment of a strong friendship between the two men. Pavan loved excursions; furthermore, he was an extremely polite person who was adept at pleasing those he wanted to please. Therefore, it comes as no surprise that he totally charmed Dobzhansky, who only referred to him as Pavanzinho [little Pavan, which can be quite affectionate rather than derogatory in Portuguese].

And so it was that the use of drosophilae for research was introduced in Brazil. This was a totally virgin field of study amongst us, meaning great facilities and guaranteed success. Dobzhansky taught basic knowledge about the drosophila, the systematics and the creation of the species in laboratories. By 1943, Pavan had already had his two first research studies published, both of which had been done in collaboration with Dobzhansky. One concerned systematics and was published in a newsletter from the Biology Department, whereas the other, on the chromosomes of the Brazilian drosophila species, was published in nothing less than PNAS – Proceedings of the National Academy of Sciences, one of the toughest journals in which to be published. This was undoubtedly an outstanding and rather expeditious start. Dobzhansky’s stay in Brazil was relatively short (six months). Nevertheless, his cooperation with the department did not cease upon his return, to the contrary. Dobzhansky took samples of Brazilian species back to the USA, especially of D. willistoni and D. prosaltans, to use them to prepare strains with balanced lethal genes, to be used in research to determine the frequency of lethal and sterile genes in natural populations.

Pavan, who completed his doctorate in 1944, was awarded a 19-month post-doctoral grant by the Rockefeller Foundation. Thus, in 1945/46, he spent time at Dobzhansky’s laboratory at Columbia University and six months at the University of Texas in Austin. He also visited several Canadian universities sponsored by the Canadian consulate.

Pavan, Brito da Cunha (standing), Dobzhansky and his daughter Sophie, at Vila Atlântica

Memória IB-USP CollectionPavan, Brito da Cunha (standing), Dobzhansky and his daughter Sophie, at Vila AtlânticaMemória IB-USP Collection

Thereafter, once he had returned, Pavan and Dobzhansky began planning a major project to be carried out in Brazil. One must keep in mind that Dobzhansky was extremely interested in doing research with Brazilian species of drosophilae, which offered great variability vs. the US species, which were fairly uniform. Therefore, it was most important for his scientific work to have comparative data from those two regions. So they agreed to conduct a project in 1948/49, involving several participants not only from Brazil but also from abroad, all of this with the financial aid of the Rockefeller Foundation. This project led to nine publications in 1950/51.

Besides Dobzhansky, this work group included Pavan, Antonio Brito da Cunha, Antonio Cordeiro (from Rio Grande do Sul), Antonio L. Cavalcanti and Chana Malogolowkin (from Rio de Janeiro), Sophie (Dobzhansky’s daughter), Martha Wedel (from Argentina), Hans Burla (from Switzerland), Boris Spasky (who worked out of Columbia University) and Marta Breuer (a German biology technician).

In 1949 Newton Freire-Maia and Pavan published “Introdução ao estudo da drosófila” [“Introduction to the study of the drosophila”] in the magazine Cultus, of Ibecc. It was a study of an instructional nature, designed for high school students, but came to be enormously successful, even among secondary school teachers and university students. The edition was sold out and copies were made. This publication helped to define the professional vocation of many students who turned to natural history because of it. I regard this as a major service to the cause of education, so lacking in support in Brazil.

Once all the excitement of conducting a joint project involving several participants from Brazil and abroad had blown over, the Biology Department resumed its calm, but with a higher standing. The project had proven to be successful in all senses and the name of the department was now regarded with respect and even with a touch of jealousy. This was a young department that, in an extremely short time, had unquestionably reached international standards. It is true that Dobzhansky’s involvement had been very important, setting the group’s scientific standards, but one must take into account that the Brazilian team, led largely by Pavan, rose to the challenge. It was a period of hard work and great enthusiasm, thanks mainly to the intellectual exchange among its participants. One lived from science and for good researchers, nothing is better or more gratifying than this.

After this stage had reached its end, when a period of peace and tranquility was expected, there arose a matter of great concern to all. The dear master and conductor of the entire process, professor Dreyfus, developed a serious health problem. His blood pressure rose and he became subject to strokes, which occurred every once in a while, obliging him to go into hospital, where he was carefully and tenderly looked after by various friends, his medical colleagues, and by laymen as well. All knew his illness was serious and that the worst might happen at any time. In this case, his chair at the university would become vacant and, according to the laws in effect then and to this day, it would be subject to public examination immediately.

Thus, strong pressure was exerted on Pavan, regarding the eventual need for him to face the examination. Dreyfus was the person who most encouraged him to prepare for the exam swiftly, so as to be able to take the latter’s place as full professor in charge of the chair. It was important to have the post-doctoral title of livre-docente to have a chance to pass the exam. This was all considered difficult and one of the most important landmarks in academic life, one that meant scientific maturity or, better stated, intellectual maturity. The need to face this challenge drove Pavan to focus solely and intensely on preparing for the examination, which was held in 1951.

Dreyfus’ health had not improved significantly, but he would still appear at the department and even participate in lectures. One of his strokes had left him partially paralyzed on the right-hand side. Although he had been relieved of his lecturing duties, he used to turn up to attend the lectures of his substitutes and was unable to check himself whenever they displeased him. He would barge right in and would start teaching the subject himself, writing on the blackboard with his left hand, with great difficulty. Pavan would often interrupt a lesson attended by Dreyfus to measure his blood pressure, fearful that it might oscillate strongly. The classes were small and there was a very close relationship between the students and the professors, so that such events were taken in stride. We were a family!

Unfortunately, the problem was incurable and in February 1952, Dreyfus died, to the dismay of the entire academic community. He had been an outstanding teacher, a man of great learning about the humanities and scientific culture, and truly a very special person who spread kindness. His death was deeply mourned.

As expected, Pavan rose to the position of provisional full professor in charge of the chair until the examination was held. As a candidate for the position, he focused fully on preparing for the examination. His post-doctoral thesis was called “Relações entre populações naturais de Drosophila and o meio ambiente” (“Relations between the natural Drosophila population and the environment) obtained on his countless excursions to several parts of Brazil.

A public exam is always risky; nobody can be sure of the outcome. Therefore, it is best to take preventive action ahead of time. Pavan felt that if Dobzhansky, who would surely vote for him, were on the examination board, few examiners would be so petulant as to go against him.

The school was did not object to including him on the examination board. Once the term for registration of those who planned to sit the examination had expired, it was found, not without a measure of relief, that only Pavan had signed up for it. This alone was half the battle won.

Alameda Glete street building, where the Biology Department used to be

Memória IB-USP CollectionAlameda Glete street building, where the Biology Department used to beMemória IB-USP Collection

The examination process was long, with several tests and a range of events that Dobzhansky, in a subsequent letter to his friends, criticized acerbically. The outcome, however, was a great success: Pavan passed, becoming the youngest full professor in charge of a chair at USP in 1953, at the age of only 33. There were no favors involved in his approval. The candidate, though rather young for the position, had fulfilled all requirements. Moreover, if one were to consider the other potential candidates, other than, perhaps, professor Antonio Brito da Silva, who in a gentlemanly act gave up his right to sign up, there was no one else who was qualified for the position. Thus, justice was done.

Back at the time of the Alameda Glete address, working hours were from Monday to Friday, from 8:00 a.m. to 6:00 p.m. and on Saturdays from 8:00 a.m. to noon, although this was often extended to 6:00 p.m. Furthermore, it was common to pass by the Biology department on Sunday morning to meet colleagues and get ready for the following week. It was equally usual for people to work at night. Actually, it was as if the department was our home. There was great harmony among all its members, who were few at the time. All in all, some 15 people. Later, it started expanding.

Pavan was a fairly liberal department head who did not want to resort to his position’s authoritarian prerogatives. One can say that this was an extremely peaceful, pleasant and productive period. The drosophilae research now proceeded with one more objective, namely, to study the effect of radiations on natural populations. Pavan and Dobzhansky undertook a new project in the department, involving several foreign researchers. Dobzhansky wanted to test new hypotheses that he had raised and, to this end, he needed several natural and isolated populations. Pavan offered him the islands of Angra dos Reis, a veritable paradise. Once again, the Rockefeller Foundation was contacted and footed the whole bill for the project.

Besides Dobzhansky, the following foreign researchers were invited: Charles Birch, from Australia, coauthor, with Andrewartha, of the then newly published The distribution and abundance of animals, which was to become very famous for the information that it brought together; Bruno Bataglia, from Italy; and Ove Frydenberg, from Denmark. From Brazil, the following were invited: Cora Pedreira, from Bahia, and Mirtes Nilo Bispo, from Pernambuco. All the other team members belonged to the Biology Department.

The project started in 1956. This timing, however, was unfortunate. Right at the start, when the entire team convened, there was a serious falling-out between Frydenberg and Dobzhansky, due to differences in their ideas. This gave rise to a highly unpleasant atmosphere. It was difficult to understand how a young researcher, who had only just got his doctorate, was so petulant as to go against the famous, the notorious old professor Theodosius Dobzhansky, revered throughout the world. I have no doubt that, in this case, the young Danish researcher was actually right. What Dobzhansky stated in his defense at the time was that he only acknowledged two types of scientific research: the pioneering sort and the non-pioneering sort. The former was good and everything else was not. The proposed research was of a pioneering nature and, therefore, was good. Of course, this argument was groundless, as was proven in practice, because the work carried out achieved results that were not even published. This episode might be better clarified by someone inclined toward the history of science. Incidentally, I think that one day a critical evaluation of the work of Dobzhansky should be undertaken, given his importance in the studies about evolution theory worldwide.

Once this multi-institutional project came to an end, things went back to normal. The Alameda Glete days were numbered, by then, as the construction of the Biology building at the Cidade Universitária campus was nearing its end. In 1960, the department moved to the new campus, but it was never the same again.

Luiz Edmundo Magalhães is a full professor of genetics and evolution and a former director of USP’s Biosciences Institute. He was also the president of the Federal University of São Carlos, from where he holds an honorary doctorate, and a visiting professor at USP’s Advanced Studies Institute and at Unifesp. This article was prepared at the invitation of the Brazilian Genetics Society and presented at the symposium “The presence of Crodowaldo Pavan in Brazilian genetics: memorial,” during the 55th Brazilian Congress of Genetics, held in September 2009 in the town of Águas de Lindoia).