ary lla B.A

mutation, migration, drift, mating system, and selection. Though the theoretical consequences of each evolu-tionary force on population genetic dynamics are well understood, the magnitudes and relative contributions of these evolutionary forces have rarely been quantified the same pathogen species. To apply knowledge of pathogen population genetics in Darwinian medicine, quantitative knowledge of each of the five evolutionary forces is desirable. The majority of research on interactions among evolutionary forces currently is based on arbitrary data sets (Hastings, 2001; Hastings and Mackinnon, 1998; Reinhold, 2002; Zeyl ogy 4*A primary goal in population genetic studies of pathogens is to reveal the evolutionary history of par