Guido Pellegrino Arrigo Pontecorvo, who liked to be known as "Ponte", was born in Pisa, Italy on 29th November 1907. He was the eldest of eight children born to non-observant Jewish Italian parents, Massimo and Maria Maroni Pontecorvo. Massimo, was a wealthy businessman who inherited his father Pellegrino Pontecorvo's successful textile company when he died in 1918. The company was said to have employed around 1500 workers and by 1920 was one of the largest textile companies in Italy. Pontecorvo's brother Bruno (1913-1993) was an Italian-born nuclear physicist, an early assistant of Enrico Fermi and the author of numerous studies in high energy physics. He is known for defecting to the Soviet Union in 1950. When asked if he knew where his brother was Guido Pontecorvo responded, "I am not my brother's keeper". His other brother, Gillo Pontecorvo (1919-2006), was a filmmaker and his best known films include La battaglia di Algeri (1966) and Burn (1969) starring Marlon Brando.
Stimulated by a high-school teacher, Pontecorvo took a degree at the University of Pisa's Faculty of Agriculture and graduated in 1928 as a Doctor of Agricultural Science. He followed this with two postgraduate courses in silkworm breeding and agrarian studies in Milan and Pisa between 1929 and 1930. After his postgraduate studies, and two years of compulsory military service, Pontecorvo worked with E Avanzi, (a plant geneticist from the Faculty of Agriculture in the University of Pisa) who was now director of an experimental agricultural institute in Trento. He soon moved to Florence to lead the cattle breeding program of the Tuscan Ispettorato Compartimentale Agrario. Here, for eight years, he organized the recording and use of weight gain and draught ability data in a successful selective breeding program applied to the Chiana and Maremmana breeds.
In 1937-38 he toured animal breeding centres, ending in Edinburgh, the venue of the 1938 International Congress of Genetics. After this he intended to go to Peru to take up an animal breeding Government contract but the contract was cancelled when war broke out and Pontecorvo was stranded in Scotland. At the same time Pontecorvo received a letter of dismissal from his Tuscan post as Italy adopted Nazi racial laws limiting the employment of persons of Jewish ancestry.
Being stranded in Edinburgh proved fortuitous because there Pontecorvo met and fell under the influence of Hermann Joseph Muller, which led to him abandoning the application of genetics for study of its fundamentals. With help from local animal breeding scientists Alick Buchanan-Smith and Alan William Greenwood he received refugee support from the Society for the Protection of Science and Learning and enrolled as Muller's student, graduating PhD in the Faculty of Science, University of Edinburgh in April 1941 with a thesis that showed that he had learned much from Muller about the exploitation of Drosophila genetics and biology. In Edinburgh on the 8th September 1939, a few days after the outbreak of World War II, he married his longstanding Swiss fiancée, Leonore (Leni) Freyenmuth and they were happily married until her death in September 1986.
In 1940 Italy declared war and, as a result, Pontecorvo was interned on the Isle of Man with other "enemy" aliens, while his Swiss wife, Leni, was advised to move to the west coast of Scotland as she was regarded as an enemy alien by marriage. Leni moved to Glasgow and received hospitality from the wife of Edward Hindle, Professor of Zoology at the University of Glasgow, who also arranged some research space for Pontecorvo when he was released in January 1941. He worked with Hindle in the Zoology Department from 1941-1943. After a year as a Carnegie Research Fellow in Glasgow and one as a lecturer in Edinburgh he received his first tenured post as lecturer in Genetics in Glasgow (1945), where he rose rapidly to be Head of the newly founded Department of Genetics becoming, in 1955, both Professor and a Fellow of the Royal Society. He became a Naturalized British citizen in 1947. Under Pontecorvo's direction Glasgow became a world famous centre for genetics research and it is clear that he was determined to make a difference and to inspire his team to make significant advances in this field. He left Glasgow in 1968 to become a research scientist at the Imperial Cancer Research Fund Laboratories, London, before retiring in 1975.
Pontecorvo made significant contributions to cattle breeding in Tuscany where he organized a wide-ranging programme of recording and selective breeding for milk yield and draught ability in two regional cattle breeds. In Edinburgh, under the influence of Hermann Joseph Muller, he abandoned the application of genetics for more fundamental studies of the nature of the gene gaining, as Muller's student, valuable experience of complex techniques in classical genetics such as radiation-induced chromosome loss and the exploitation of hybrid sterility. After "war-work" in Glasgow investigating meiosis in the hamster and louse, Pontecorvo started working on the genetics and heterokaryosis of Penicillium, and also started to explore the possibilities for genetic analysis in bacteria (at a time when many thought that bacteria lacked heredity).
He sought, and found in Aspergillus nidulans, a microorganism in which "fine genetic analysis" would make it possible to explore genetically Muller's insight into mutation and recombination as alternative ways to understand the internal structure of the gene. Clear thinking about the roles of nuclear fusion and chromosome segregation in genetics, coupled with the discovery of Aspergillus diploids, haploidization and mitotic recombination (the Parasexual cycle), led Pontecorvo to propose that such "alternatives to sex" applied to cells in culture would provide the needed way ahead in human and medical genetics. These were far-seeing ideas that after many years achieved fruition as "somatic cells genetics".
Pontecorvo and Leni's warm and hospitable natures were widely appreciated as can be seen in their home visitors' book which was signed by friends and colleagues who visited and stayed with them at their various homes in Glasgow and London over the years. Pontecorvo was loved and admired by his large network of genetics friends and colleagues and the research and personal correspondence in this collection highlights his life long friendships with notable geneticists from all over the world.
Aside from genetics Pontecorvo's life long passion was alpine plant photography and ecology. He set aside each summer for pursuits to some of the world's most spectacular alpine regions, and his collection contains thousands of slides of alpine flowers and their habitats which he was using to research a book on plants at high altitudes (sadly this was never finished). He visited various mountains and national parks in the USA in the 1950s and 1960s, in the 1970s he travelled to Iran to study the flora of the Fars region and Mt Elburz. He explored the Himalayas in India and the Tien Shan and Kunlun mountains in China in the 1980s. These trips were organized with the help of The Royal Society or at the invitation of local academies and were often combined with lecture tours and courses. Ponte often made excursions to mountains a precondition for accepting invitations.
He was the founder of the genetics of Aspergillus nidulans, a relative of Penicillium, and his research on haploids and recombination led to his discovery of the Parasexual cycle. He was the first person to file a patent for a biological process
Pontecorvo also spent a significant amount of time researching alpine plants in his Swiss chalet in St Luc and it was here that he died in 1999 after a fall when he was out foraging for mushrooms. His life and academic achievements were celebrated at Pontefest, an event organised by his daughter Lisa Pontecorvo and the Imperial Cancer Research Fund, for friends and colleagues to reminisce and celebrate his contributions to science and the influence he had on their lives.
This biography was compiled from Pontecorvo's 1964 CV and his biographical notes for the Royal Society, and from biographical pieces on Pontecorvo including:
- Pontecorvo "Ponte" 1907-1999 by Bernard L Cohen in Genetics, Vol 154, pp 497-501, February 2000;
- Biographical Sketch of Pontecorvo by Professor Obaid Siddiqi published at the beginning of Topics in Genetic Analysis: selected papers of G Pontecorvo, Raman Professor, 1982-1983, (Indian Academy of Sciences, 1985).