Cavalli-Sforza initiated a new field of research by combining the concrete findings of demography with a newly available analysis of blood groups in an actual human population. He also studied the connections between migration patterns and blood groups. Writing in the mid-1960s with another genetics student of Ronald A. Fisher, Anthony W. F. Edwards, FRS, Cavalli-Sforza pioneered statistical methods for estimating evolutionary trees. Edwards and Cavalli-Sforza wrote about trees of populations within the human species, where genetic differences are affected both by treelike patterns of historical separation of populations and by spread of genes among populations by migration and admixture. Many of these influential and fundamental early papers were reprinted in 2018 in a volume focusing on A. W. F. Edwards, and dedicated to Cavalli-Sforza and Ian Hacking. In later papers, Cavalli-Sforza has written about the effects of both divergence and migration on human gene frequencies. While Cavalli-Sforza is best known for his work in genetics, he also, in collaboration with Marcus Feldman and others, initiated the sub-discipline of cultural anthropology known alternatively as coevolution, gene-culture coevolution, cultural transmission theory or dual inheritance theory. The publication made use of models from population genetics and infectious disease epidemiology to investigate the transmission of culturally transmitted units. This line of inquiry initiated research into the correlation of patterns of genetic and cultural dispersion. Cavalli-Sforza conducted several studies of how language differences may serve as barriers to gene flow between adjacent human populations. His studies of human migration have tested hypotheses of linguists Merritt Ruhlen and Joseph Greenberg about language "superfamilies". The hypothesized superfamilies are controversial among other linguists.
Books
Cavalli-Sforza has summed up his work for laymen in five topics covered in Genes, Peoples, and Languages. According to an article published in The Economist, the work of Cavalli-Sforza "challenges the assumption that there are significant genetic differences between human races, and indeed, the idea that 'race' has any useful biological meaning at all". The book illustrates both the problems of constructing a general "hereditary tree" for the entire human race, and some mechanisms and data analysis methods to greatly reduce these problems, thus constructing a fascinating hypothesis of the recent 150,000 years of human expansion, migration, and human diversity formation. In the book Cavalli-Sforza asserts that Europeans are, in their ancestry, about two-thirds Asian and one-third African. Cavalli-Sforza's The History and Geography of Human Genes is a standard reference on human genetic variation. Cavalli-Sforza also wrote The Great Human Diasporas: The History of Diversity and Evolution. Earlier, in the 1970s, he and Walter Bodmer wrote what was the standard textbook on modern human genetics, and was also a basic reference for population genetics more generally, as the field was at the time, The Genetics of Human Populations. WHFreeman, 1971. The two, with Bodmer as first author, later wrote another more basic text, Genetics, Evolution, and Man WHFreeman, 1976. Along with his 1994 book these are essentially classical presentations of human genetics before the genomics era began providing very much more detailed data.
Death
Professor Cavalli-Sforza died on 31 August 2018, at the age of 96 at his home in Belluno, Italy.
