Functional genomics perspectives on Biomphalaria glabrata

Abstract

Biomphalaria glabrata is a freshwater snail that transmits schistosomiasis, a parasitic disease affecting over 250 million people worldwide. Despite decades of human-focused interventions, the disease burden remains high, particularly in sub-Saharan Africa, where infection rates in snail vectors have risen over the past 25 years. These trends underscore the urgent need for effective snail control strategies to support elimination programs. Traditional chemical molluscicides pose environmental risks, motivating research into alternative approaches. This thesis applies functional genomics to investigate two key aspects of B. glabrata biology relevant to control: the influence of diet on gene regulation and the mechanisms underlying RNA interference (RNAi). Bulk RNA sequencing was conducted to assess transcriptional responses to different diets. Results show that dietary composition substantially reprogrammes the snail transcriptome, impacting pathways involved in growth, reproduction, and survival. These findings enhance understanding of how diet shapes gene–phenotype relationships and highlight candidate pathways that could be targeted to regulate snail populations. RNAi, an important tool for functional genomics, was also explored. Comparative genomic analyses revealed that classical RNAi-spreading proteins, such as Systemic RNAi Defective (SID) proteins, are absent in B. glabrata and related some other schistosomiasis vectors. Instead, systemic RNAi is likely mediated by vesicle-trafficking proteins, advancing knowledge of molluscan RNAi biology. Attempts to apply RNAi experimentally for gene silencing faced technical challenges, with limited success despite methodological refinements. These efforts nonetheless provided valuable insights for improving RNAi protocols in snails. Collectively, this work deepens understanding of the diet–genome–phenotype nexus in B. glabrata and clarifies aspects of its RNAi machinery. By addressing fundamental gaps, it provides a foundation for future functional validation of candidate genes and the development of novel, environmentally sustainable snail control strategies to aid schistosomiasis elimination.

Date of Award	Dec 2025
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Paul McVeigh (Supervisor) & Geoffrey Gobert (Supervisor)