Eclipse of the gene and the return of divination

Research in the field of epigenetics challenges the assumption on which the molecular genetics of the past 50 years has been based, namely, genetic determinism. This paper reviews the social science literature that considers the social effects of the application of molecular genetics and genetic testing in connection with Mendelian conditions. It is argued that anthropologists must now go farther and respond to the challenge posed by current moves toward the implementation of genetic profiling and testing for susceptibility genes. Following a discussion of ontológica! problems associated with molecular genetics raised by philosophers and biologists who subscribe to epigenetics, current knowledge about molecular and population genetics of late-onset Alzheimer's disease and cross-cultural findings about the epidemiology of this disease are introduced. These findings illustrate the provisional nature of these bodies of knowledge and the complexity associated with susceptibility genes, which makes estimations of probabilities of individual risk unrealistic. A controlled clinical trial is discussed in which first-degree relatives of Alzheimer's disease patients are genotyped for risk for late-onset Alzheimer's disease. In conclusion, the social implications of testing for susceptibility genes are discussed, with comments about the role that anthropologists might play in future research.