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Cavalli-Sforza, Luigi Luca

genes genetics linked human

(1922– ) Italian geneticist: leading figure in the development of population genetics.

Cavalli-Sforza graduated in medicine at Pavia in 1944, and afterwards worked in bacterial genetics in Cambridge, Milan, Parma and Pavia before he became professor of genetics at Stanford, CA, from 1970–92. Population genetics is concerned with the links between human genes and the location and movement of races or peoples: it can use both living and long-dead material for DNA studies of genes, and its results can be correlated with language and cultural characteristics. Thus the Basque people, mainly found in northern Spain, have a high incidence of a gene linked with the Rhesus-negative blood group: they also share a distinctive language, one of the very few non-Indo-European languages in Europe. Cavalli-Sforza showed that to understand human evolution, ‘genetic drift’ (the Sewell Wright effect) as well as natural selection is important: for this he used the Church’s 300-year archive of births, marriages and deaths for 100 Italian villages, and linked this with his sampling of blood from present villagers to find the frequency of A,B,O blood groups. Others have since worked on genes found in mitochondrial DNA, which is passed only in the female line, and changes only by mutation, at a rate of 2–4% per million years. Work on these lines has made firm the view that modern Homo sapiens are all descended from one group which evolved in Africa a few hundred thousand years ago.

Studies on New World populations using DNA, linguistic and dental evidence all point to three waves of migration from Siberia over 10 000 years ago, into North America when it was then linked by land (Beringia). At about the same time the earliest neolithic farmers expanded from the Middle East into Mediterranean Europe, reaching France, Britain and Scandinavia about 6000 years ago: thereafter both mixing with and overwhelming the native hunter–gatherers, who had different frequencies for the 95 genes studied. Cavalli-Sforza’s classic History and Geography of Human Genes (1994) surveys migrations in all continents; his conclusions are not universally accepted, as is inevitable in a developing science with much to offer archaeology and anthropology.

Cavazzoni (also called da Bologna and d'Urbino), Marco Antonio [next] [back] Cavalli (real name, Caletti), Pier Francesco

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