New Gene Study Enters Indo-European Fray
Bower, Bruce, Science News
Analysis of DNA from modern humans supports other indications that a northward migration of farmers from ancient Turkey and the Middle East, beginning around 9,000 years ago, shaped Europe's genetic geography. The DNA data also bolster a controversial theory that links this agricultural expansion to the spread of Indo-European languages, contend Alberto Piazza, a geneticist at the University of Torino, Italy, and his colleagues.
However, the genetic finds may also lend weight to a contrary proposal, the researchers add: that nomads from the central Eurasian Yamna culture spread Indo-European languages shortly after they invented wheeled vehicles approximately 5,500 years ago (SN: 2/25/95, p.120).
"It is possible that both expansions were responsible for the spread of different subfamilies of Indo-European languages, but our genetic data cannot resolve their relative importance," the researchers conclude in the June 20 Proceedings of the National Academy of Sciences.
Their investigation employs blood samples gathered earlier as part of an analysis of worldwide human genetic variation. Study coauthor L. Luca Cavalli-Sforza, a geneticist at Stanford University, directed the international project. Cavalli-Sforza and his colleagues describe those findings in The History and Geography of Human Genes (1994, Princeton University Press).
Piazza's team analyzed DNA from people in Europe and adjacent parts of central Eurasia and the Middle East. The researchers calculated the frequency of certain structural variations in 95 genes. They then used a statistical procedure to sort through the catalog of measured genetic differences, looking for geographic patterns of variation.
From about one-quarter of the measured genetic differences they extracted a pattern of numerous DNA changes in Turkey and the Middle East, with genetic mutations gradually declining in northern locales. …