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Many parasites utilize asexual and sexual reproduction and multiple hosts to complete their life cycles. How these taxa avoid inbreeding is an essential question for understanding parasite evolution and ecology. Aquatic trematodes that require multiple host species may benefit from diverse genetic parasite assemblages accumulating within second intermediate hosts prior to sexual reproduction in definitive hosts. However, Cotylurus species are able to utilize the same snail species as first and second intermediate hosts, potentially resulting in the accumulation of genetically identical clones (clonemates) prior to sexual reproduction. In this study, we developed and analysed novel microsatellite loci to determine if clones are accumulating within snail hosts prior to ingestion by bird hosts and the effects this could have on parasite inbreeding. Contrary to previous studies of aquatic trematodes, significantly large numbers of clonemates were present within snails, but full-sibs were not. Genetic structure was present over a relatively small geographical scale despite the use of vagile definitive hosts. Phylogenetic analysis identified the Cotylurus sp. clones as belonging to a single species. Despite the presence of clones within snails, mating between clones/selfing was not common and heterozygosity is maintained within individuals. Potential issues with clones mating may be mitigated by the presence of snails with numerous clones, the consumption of many snails by bird hosts and parasite clone recognition/avoidance. Use of the same host species for multiple life stages may have advantages when parasites are able to avoid inbreeding and the required hosts are common., (© 2022 John Wiley & Sons Ltd.)

Mutation of the LRRK2 gene has been associated with autosomal dominant parkinsonism. An R1441C pathogenic substitution was identified in Family D, a large Western Nebraskan kindred, with four members demonstrating pleomorphic pathology at autopsy. One member of this family displayed tau pathology suggestive of progressive supranuclear palsy (PSP). To evaluate the influence of mutation at the R1441 residue in this disorder we screened a series of 242 pathologically confirmed PSP cases. No evidence was found for the presence of a mutation at this codon in our series. These data would suggest that this Lrrk2 variant does not contribute in susceptibility to PSP.