[Man and the diversity of his genome. An extraordinary phase in the history of population genetics].

Population genetics is almost eighty years old, but benefited only very recently from the advantages of direct DNA analysis. Nevertheless, much knowledge had already accumulated and was completely confirmed by the study of DNA markers. Major benefits of the latter came with microsatellites. It allowed to discover an error made with classical markers but even more seriously with RFLPs, because of the practically involuntary sampling of individuals almost exclusively of European origin for the detection of polymorphisms. Among other evolutionary application of microsatellites, the most attractive is their very recent use for dating population separations during the recent migration out of Africa of modern humans. They confirm the theory that this expansion was quite recent. Single nucleotide substitutions are the major material of evolution, and so far markers of this kind were rare. A new method, DHPLC, is excellent for their detection and testing. In humans it has been applied almost exclusively to the Y chromosome, and in a year it has given a completely new picture of Y chromosome genetics. Some applications of statistical methods to genetic geography of classical markers and ADN markers will show the power of the geographical approach, and therefore the need of a wide collection of population samples, as will be made possible by the HGDP (Human Genome Diversity Project).