Genome of the rams horn snail Biomphalaria straminea: an obligate intermediate host of schistosomiasis

Wenyan Nong, Yifei Yu, Madeleine Emma Aase-Remedios, Yichun Xie, Wai Lok So, Yiqian Li, Cheuk Fung Wong, Toby Baril, Sean Law, Sheung Yee Lai, Jasmine Haimovitz, Thomas Swale, Shan-shan Chen, Zhen-peng Kai, Xi Sun, Zhongdao Wu, Alexander Hayward*, David Ellard Keith Ferrier*, Jerome Hui*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Background: Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Infection by Schistosoma mansoni in humans results when cercariae emerge into water from freshwater snails in the genus Biomphalaria and seek out and penetrate human skin. The snail Biomphalaria straminea is native to South America and is now also present in Central America and China, and represents a potential vector host for spreading schistosomiasis. To date, genomic information for the genus is restricted to the neotropical species Biomphalaria glabrata. This limits understanding of the biology and management of other schistosomiasis vectors, such as B. straminea.

Findings: Using a combination of Illumina short‐read, 10X Genomics linked‐read, and Hi‐C sequencing data, our 1.005 Gb B. straminea genome assembly is of high contiguity, with a scaffold N50 of 25.3 Mb. Transcriptomes from adults were also obtained. Developmental homeobox genes, hormonal genes, and stress-response genes were identified, and repeat content was annotated (40.68% of genomic content). Comparisons with other mollusc genomes (including Gastropoda, Bivalvia, and Cephalopoda) revealed syntenic conservation, patterns of homeobox gene linkage indicative of evolutionary changes to gene clusters, expansion of heat shock protein genes, and the presence of sesquiterpenoid and cholesterol metabolic pathway genes in Gastropoda. In addition, hormone treatment together with RT-qPCR assay reveal a sesquiterpenoid hormone responsive system in B. straminea, illustrating that this renowned insect hormonal system is also present in the lophotrochozoan lineage.

Conclusion: This study provides the first genome assembly for the snail B. straminea and offers an unprecedented opportunity to address a variety of phenomena related to snail vectors of schistosomiasis, as well as evolutionary and genomics questions related to molluscs more widely.
Original languageEnglish
Article numbergiac012
Number of pages13
Early online date15 Feb 2022
Publication statusE-pub ahead of print - 15 Feb 2022


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