Research has continued on developing methodology for analyzing molecular population genetics data. A statistical test was devised for determining the presence of geographic subdivision of populations that uses molecular variation in samples of DNA sequences from two or more different localities. A permutation method was used to assess the statistical significance of the test statistic. Work has begun to study the statistical properties of the sample site frequency spectrum F=(f(i), 1 is less than or equal to i is less than or equal to n-1) where f(i) equals the number of segregating nucleotide sites in a random sample of n genes with frequency i/n, 1 is less than or equal to i is less than or equal to n-1. For selectively neutral variation, the distribution of the sample site frequency spectrum is a mixture of multinomials and the mixing distribution depends on the genealogical history of the sample. This representation is important because it can be exploited to make inferences about the evolutionary forces responsible for the observed variation. Work is continuing on describing the effects of strongly selective substitutions on the coalescent process. Of particular interest is when two or more strongly selective mutations are simultaneously going to fixation.
