A number of developments seemingly unrelated to each other have recently begun to make the genetic study of different human populations both more meaningful and of greater urgency than before. Polymorphisms in nuclear DNA now offer yet another tool to study the origins of our ancestors. Previously unavailable sources of information are the maternally inherited mitochondrial polymorphisms and the paternally inherited Y chromosome polymorphisms. In the absence of recombination, these provide new means of studying inheritance and mutation. Population genetics used to be the playground of a few theoretically inclined, mathematically oriented researchers working with exotic populations. This picture is now rapidly changing, as disease genes and their mutations enter the scene. While the study of disease-causing mutations rather than of silent polymorphisms would not appear to be very different, it is the involvement of large numbers of molecular, cytogenetic, and clinical researchers in this area that makes the difference. The population-genetic implications of the frequency and distribution of the prevalent ΔF508 mutation in the CFTR gene causing cystic fibrosis is already becoming a classic. Similar equally fascinating stories about the origin and spread of single and multiple mutations of numerous other genes are being unveiled. Importantly, the different mutations often lead to different clinical features, and many may affect selection.
While these developments are occurring on the scientific scene, the society in which we live is undergoing rapid changes that have a bearing on the distribution of our genes. For instance, in Europe the growth and stabilization of the European Union may begin to make our continent a genetic melting pot. In contrast, in some parts of Europe, particularly in the former Soviet Union, strong and determined forces favor nationalism as a means of cultural, ethnic, and political survival. This could lead to genetic neoisolation. Finally, population movements of considerable magnitude continue to create new founder groups with or without significant admixture with the receiving populations. In Europe, the more industrialized northern nations have received and continue to receive millions of people from further south who arrive in search of work and security, mimicking the great overseas emigrations of Europeans in the past. These gene movements have both medical and social implications not only for the immigrants themselves but also for the countries in which they settle.
