Transmission mode affects the population genetic structure of Daphnia parasites

Abstract

Parasite life cycle variation can shape parasite evolution, by predisposing them towards different population genetic structures. We compared the population genetic structure of two co‐occurring parasite species of Daphnia, to collect evidence for their expected transmission modes. The ichthyosporean Caullerya mesnili has a direct life cycle, whereas the microsporidian Berwaldia schaefernai is hypothesized to require passage through a secondary host. The parasites were collected from three geographically isolated Daphnia populations. The nucleotide variation in the internal transcribed spacer (ITS) region was assessed at the within‐individual, within‐population and among‐population levels, using amova. We detected significant partitioning at all levels, except for a lack of among‐population variation in Berwaldia. This was confirmed by neighbour‐joining and principal component analyses; Caullerya populations were distinct from each other, while there was much overlap among parasite isolates representing different populations of Berwaldia. This all implies a higher amount of gene flow for Berwaldia, consistent with the hypothesized transmission mode.

Genetic diversity and effect of temperature and pH on the growth of Macrophomina phaseolina isolates from sunflower fields in Hungary

“…The analysis of the population genetic structure of generalist pathogens such as M. phaseolina is an approach to understand the dynamics of such pathosystems. Molecular markers are necessary to partition the genetic variance into within-and among-population components, which is the prerequisite for characterizing the genetic structure of pathogens [27][28][29]. In the present work the effect of different temperatures and pH on the growth of 48 M. phaseolina isolates and the genetic variation between the isolates was studied using RAPD assay and PCR-RFLP on the rDNA region.…”

Natural distribution and co-infection patterns of microsporidia parasites in theDaphnia longispinacomplex

“…Apart from B. schaefernai previously studied in detail (Wolinska et al 2011b), we could identify 1 additional lineage, Gurleya vavrai, to the species level. Although the analysed SSU rDNA fragment matched sequences assigned to 2 species: G. daphniae (with a complete match) and G. vavrai (differing by a single point mutation i.e.…”

Microsatellite and single‐nucleotide polymorphisms indicate recurrent transitions to asexuality in a microsporidian parasite

“…However, as these studies were based on rRNA markers that are usually duplicated within single genomes, mixed infections could have been confounded with diversity among paralogues of a single parasite clone (see, for instance, O'Mahony et al, 2007). It was suggested that a direct life cycle would lead to a higher differentiation among populations (Wolinska et al, 2011). Indeed, Enterocytozoon bieneusi, a microsporidian with direct life cycle, shows highly structured populations in the human host, with no recombination (Li et al, 2012).…”