African Human Genome Initiative | Profile (original) (raw)

Spier 2003

Italian scientist Luigi Cavalli-Sforza has been at the cutting edge of research into genetics and language for almost half a century. He is in South Africa to attend the Human Genome In Africa Conference

Abiding questions about the origins of humanity guided the research of a young Italian scientist who, in the heady years of the late 1940s and early 1950s, was among the first to ask whether the genes of modern populations contain a historical record of the human species.

In the intervening half century, the exploration and development of these ideas cannot be spoken about without recourse to the lifetime's work of Luigi Luca Cavalli-Sforza.

In the vividly ground-breaking period of the first decade after World War 2 – from which maverick scientists James Watson and Francis Crick emerged, for instance, with their identification of "the secret of life", the DNA structure, the young Cavalli-Sforza began to open a new field of research by combining the study of the demography of the past few centuries with an analysis of human blood groups in a real population.

Today, at 80, he remains actively engaged in the sphere of genetic medicine and research, a frontier of science and human understanding the exploration of which he is convinced developing countries like those of Africa must join if their populations are to benefit from the immense immediate and potential rewards.

Cavalli-Sforza was born in Genoa in 1922, the year in which Benito Mussolini established his Fascist dictatorship in Italy.The dominant influence of 'Il Duce' – who took Italy into World War Two on Nazi Germany's side in 1940 – was the sustained backdrop to Cavalli-Sforza's young life and early student days.

Yet it might come as a surprise that, as he experienced it, it was not a grim backdrop. He is candid in acknowledging that its impact on his early life was "only positive". It meant, for instance, being drawn into "adventures like those of the boy scouts, of skiing and walking". And it was on the strength of his involvement in these activities as a teenager that he had opportunities to travel ... "to New York when I was 14, and to several places in South America when I was 15".

A year later, when he became a student at 16, "I started learning about the negative things about fascism". He enrolled at the University of Pavia in 1938.

"I was very lucky, because the fact of having chosen to join the medical faculty, which was almost accidental, kept me free from conscription for practically all the duration of the war."He graduated in 1944, in the year after Mussolini's capitulation, with an MD in medicine and surgery.

Looking back, he recognises that his interest in tracking human origins was spurred by the "early work by Robert Race, Arthur Mourant, and R A Fisher especially, using ABO and Rh blood groups to understand early human history".

It was this line of scientific enquiry that shaped his "interest in developing systematic methods of analysis". But there was no immediate prospect of doing anything of the sort in war-ravaged Italy. "I was very anxious to go to England to find good teaching of research, but I could not do it until three years after the end of the war.

After all, we were enemies during the war!." And once he got there, the other difficulty was that "Cambridge does not recognise the degrees of other universities except of Oxford and Edinburgh". He was undaunted, however.

"I was given a job involving research and teaching, and I started a course – probably the first ever – of microbial genetics." His status had curious implications: "Although I was lecturing – but was not a lecturer or a student – I was not able to go to the library! To enable to do so, they gave me an honorary MA.

"I believe," he adds wryly, "it is called 'becoming an honest man'." Leaving Cambridge in 1950, he returned to Italy, where, until 1957, he was director of research in microbiology at the Istituto Sieroterapico Milanese in Milan.

For three years, until 1960, he was lecturer in genetics and in statistics in the faculty of sciences at the Universities of Parma and Pavia. He became professor of genetics at Parma in 1960, and from 1962 to 1970, was professor of genetics and director of the Institute of Genetics at the University of Pavia.

Cavalli-Sforza made a decisive shift in 1970: he crossed the Atlantic and began an association with Stanford University that, as emeritus professor in the School of Medicine since 1992, continues today. It was, he acknowledges, a "new departure". "It became much easier to do research in an environment which is optimised for almost any particular type of work ...

in which there is a great number of specialists in almost every subject who are usually ready to collaborate and to advise." There were very few scientists in Italy at the time, and the academic environment was not too exciting." His gaining dual citizenship was also, in a sense, a step towards becoming more of a "citizen of the world", occupying intellectual territory that straddles national boundaries.

While there was certainly no question of being "torn between two nations", he recognises the contrasts: "Italy tends to do what America does, with a delay of months, years or decades, depending on what you are looking at," he says, but adding with undisguised pride: "Of course, with certain of things, with food, and aesthetics and a few others, Italy is ahead!" Stanford was also the base from which he travelled widely, doing much work in different parts of Africa, for instance, "which I have learnt to love".

It all began almost exactly 50 years ago.

"I started research as a bacterial geneticist, but I loved quantitative studies, mathematical models and statistical analysis. Evolution has been the object of much mathematical research.

"When I was able to start some research in another field, it presented an opportunity to find the solution to a controversy - whether chance (in the form of random genetic drift) is important in evolution – by combining the study of the demography of the past few centuries with the analysis of human blood groups in a real population."This can be done practically only in humans - the demography of other organisms is very difficult.

And the results of that research helped me to think of a method for reconstructing human evolutionary history on the basis of genetic data from extant populations." Cavalli-Sforza, widely honoured in Italy, France, Germany, Britain, the United States and Japan, has been recognised by his peers as "the world's expert on human genetic diversity and what it tells us about the phylogenetic tree of human populations".

He is acknowledged as having realised that understanding human evolution "requires the knowledge of both genetic mechanisms and cultural, especially linguistic, features".

By collecting and testing genes from a host of different populations, as well as by analysing historical, demographic, linguistic and other data, he was able to "reconstruct the origin of ancient migration, creating a model of diffusion of culture in the Neolithic Age".

His work has encompassed genetic investigations of pre-colonial populations, especially pygmies of Africa, one of the few remaining groups of hunter-gatherers, and studies of the genetic consequences of technological development, particularly the spread of agriculture from its area of origin, the Middle East, to Europe.

From this and other research, he was able to demonstrate that "genetic and cultural data converge in furnishing a convincing explanation of human evolution".

These great themes are covered in his acclaimed books, The Great Human Diasporas: The History of Diversity and Evolution – which his son, television and movie writer Francesco, helped him to write – and Genes, Peoples, and Languages.

The latter title has been praised by fellow scientist Jared Diamond for, among other things, "demolishing scientists' attempts to classify human populations into races in the same way that they classify birds and other species into races".

Cavalli-Sforza himself has written: "The classification into races has proved to be a futile exercise." Genetic research, he has argued, undermines "the popular belief that there are clearly defined races" and will "contribute to the elimination of racism." The idea of race in the human species "serves no purpose".