Comparative genetic diversity of parasites and their hosts: population structure of an urban cockroach and its haplo-diploid parasite (oxyuroid nematode)

Few studies have investigated the genetic structure of both host and parasi te populations at a level of populations and at a level of individuals. We investigated the genetic structure of the urban cockroach Blattella germani ca and its oxyuroid parasite Blatticola blattae. Random amplified polymorph ic DNA (RAPD) markers were used to quantify genetic diversity between and w ithin four populations (from two cities in France) of the host and its para site. Diversity based on phenotypic frequencies was calculated for each RAP D marker using Shannon-Wiener's index. We used multivariate analyses to tes t the significance of genetic differentiation between host and parasite pop ulations. Analysis of molecular variance was also used. Both methods gave s imilar results. Diversity between pairs of individuals was estimated by Nei & Li's index. Genetic diversity was higher within host or parasite populat ions (80% and 82%, respectively, of explained diversity) than between host or parasite populations (20% and 18%, respectively, explained diversity). T he genetic distances between pairs of parasite populations (or individuals) were not correlated with the genetic distances between the corresponding p airs of host populations (or individuals).