Isolation, characterization and PCR multiplexing of microsatellite loci for two sub-species of terrestrial isopod Porcellio dilatatus (Crustacea, Oniscidea)

Abstract

Several microsatellite markers have already been developed for different terrestrial isopod species such as Armadillidium vulgare, A. nasatum and Porcellionides pruinosus. In all these species, the endosymbiont Wolbachia has a feminizing effect that generates a female bias in sex ratio and reduces the number of reproductive males. Thus this can potentially decrease the genetic diversity of host populations. However, in some other isopod species, Wolbachia induces cytoplasmic incompatibility (CI); the most commonly described effect of Wolbachia in arthropods. The CI by rendering some crossings incompatible can reduce the gene flow and strengthen genetic differentiation between isopod populations. To date, the influence of Wolbachia inducing CI on population structure of terrestrial isopods has never been investigated. In this study, we developed 10 polymorphic microsatellite markers shared by two sub-species of Porcellio dilatatus. Crossings between the two sub-species are partially incompatible due to two CI-inducing Wolbachia strains. These new microsatellite markers will allow us to investigate the effect of CI on host genetic differentiation in this species complex.

Experimental evidence of Wolbachia introgressive acquisition between terrestrial isopod subspecies

“…Each individual was also tested for infection with Wolbachia by amplifying the bacterial gene gatB ( Baldo et al 2006 ). The gatB primers were used in combination with those of the P43 microsatellite molecular marker ( Michaud et al 2016 ), as an amplification control, in the same multiplex. PCR conditions were the same as described above.…”

“…We aimed to investigate nuclear genome admixture between “ dilatatus ” and “ petiti ” during the course of the experiments . To this end, we used 10 microsatellite molecular markers: P3, P13, P23, P25, P30, P36, P39, P40, P43, and P47 ( Michaud et al 2016 ). Three multiplexes of loci were designed: one grouping the P3, P25, and P47 loci, another the P30, P40, and P43 loci, and the third grouping loci P13, P23, P36, and P39.…”