{"doi":"10.1101/2022.06.09.495507","title":"<i>PTC2</i> region genotypes counteract <i>Biomphalaria glabrata</i> population differences between M-line and BS90 in resistance to infection by <i>Schistosoma mansoni</i>","abstract":"Abstract Background Biomphalaria glabrata is a snail intermediate host for Schistosoma mansoni , a trematode responsible for human schistosomiasis. BS90 is one of the most well studied strains of B. glabrata owing to its high resistance to infection by most strains of S. mansoni . An F2 mapping study from 1999 identified two RAPD markers that associated with what appeared to be single-locus, dominant resistance by the BS90 population relative to the susceptible M-line population. One marker cannot be mapped, but the other, OPM-04 , maps to within 5 Mb of PTC2 , a region we recently showed has a very large effect on resistance within another snail population challenged by the same strain of parasite (PR1). Here we tested the hypothesis that the PTC2 region contains the causal gene/s that explain the iconic resistance of BS90 snails. Methods We used marker-assisted backcrossing to drive the BS90 version of the PTC2 region (+/-∼ 1 Mb on either side) into an M-line (susceptible strain) genetic background, and the M-line version into a BS90 genetic background. We challenged the offspring with PR1-strain schistosomes and tested for effects of allelic variation in the PTC2 region in a common genetic background. Results Relative to M-line haplotypes, the BS90 haplotype actually confers enhanced susceptibility. So we reject our original hypothesis. One possible explanation for our result was that the causal gene linked to OPM-04 is near, but not in the PTC2 block that we introgressed into each line. So we used an F2 cross to independently test the effects of the PTC2 and OPM-04 regions in a randomized genetic background. We confirmed that the BS90 haplotype confers increased susceptibility, and we see a similar, although non-significant effect at OPM-04 . We discuss possible reasons why our results differed so dramatically from those of the 1999 study. We also present PacBio assemblies of the PTC2 and flanking region in BS90 and M-line, compare with previously published PTC2 haplotypes, and discuss candidate genes that might be behind the enhanced susceptibility of the BS90 haplotype.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2022,"id":308966,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9508,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":466202,"name":"Stephanie R. Bollmann","orcid":"0009-0007-5588-878X","position":1,"is_corresponding":false},{"id":331447,"name":"Jacob A. Tennessen","orcid":"0000-0002-5015-4740","position":2,"is_corresponding":false},{"id":466206,"name":"Michael S. Blouin","orcid":"0000-0002-8439-2878","position":0,"is_corresponding":true}],"reference_count":35,"raw_metadata":null,"created_at":"2026-07-19T00:33:07.132912Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}