Population Genetics Models for the Statistics of Dna Samples under Different Demographic Scenarios—maximum Likelihood versus Approximate Methods

The interaction of demography and genetics is of basic importance for the genetic structure of human as well as animal and plant populations. The impact is visible particularly in genetic epidemiology, as well as in physical anthropology and molecular ecology. Genetic epidemiology is a branch of science which is concerned with the distribution and evolution of genetic diseases in human populations. Many of these populations went through demographic events such as bottlenecks, splits and admixtures (Weiss, 1993). The entire modern human population resulted from a major expansion, which started 50– 100 thousand years ago (Relethford, 2001). These demographic events resulted in an uneven distribution of genetic disorders in different human populations. Typical examples are the occurrence of the mutation causing the Tay–Sachs disease in Ashkenazi Jews (Weiss, 1993, pp. 183–184), and the occurrence of diabetes in Amerindians (Weiss, 1993, Table 10.4). In addition, under suitable assumptions, all individuals with a given disease mutation can be considered a growing subpopulation originating from the individual in whom the original disease mutation occurred. This observation helps in developing methods mapping disease genes (Kaplan et al., 1995; Pankratz, 1998).