title: Hyperdiverse gene cluster in snail host conveys resistance to human schistosome parasites.
abstract: Schistosomiasis, a neglected global pandemic, may be curtailed by blocking transmission of the parasite via its intermediate hosts, aquatic snails. Elucidating the genetic basis of snail-schistosome interaction is a key to this strategy. Here we map a natural parasite-resistance polymorphism from a Caribbean population of the snail Biomphalaria glabrata. In independent experimental evolution lines, RAD genotyping shows that the same genomic region responds to selection for resistance to the parasite Schistosoma mansoni. A dominant allele in this region conveys an 8-fold decrease in the odds of infection. Fine-mapping and RNA-Seq characterization reveal a <1Mb region, the Guadeloupe Resistance Complex (GRC), with 15 coding genes. Seven genes are single-pass transmembrane proteins with putative immunological roles, most of which show strikingly high nonsynonymous divergence (5-10%) among alleles. High linkage disequilibrium among three intermediate-frequency (>25%) haplotypes across the GRC, a significantly non-neutral pattern, suggests that balancing selection maintains diversity at the GRC. Thus, the GRC resembles immune gene complexes seen in other taxa and is likely involved in parasite recognition. The GRC is a potential target for controlling transmission of schistosomiasis, including via genetic manipulation of snails.
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Tennessen
authors.affiliation: CNRS, UMR 5244, Ecologie et Evolution des Interactions (2EI), Université de Perpignan Via Domitia, Perpignan, France.
authors.forename: André
authors.initials: A
authors.lastname: Théron
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Melanie
authors.initials: M
authors.lastname: Marine
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Jan-Ying
authors.initials: JY
authors.lastname: Yeh
authors.affiliation: CNRS, UMR 5244, Ecologie et Evolution des Interactions (2EI), Université de Perpignan Via Domitia, Perpignan, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Rognon
authors.affiliation: Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Blouin
mesh_terms: D000818:Animals; D014644:Genetic Variation; D006790:Host-Parasite Interactions; D006801:Humans; D005810:Multigene Family; D012550:Schistosoma mansoni / Q000502:physiology*; D012555:Schistosomiasis mansoni / Q000469:parasitology*; D012908:Snails / Q000235:genetics* / Q000276:immunology / Q000469:parasitology*; D014900:West Indies