Genome of the ramshorn snail Biomphalaria straminea an important intermediate vector of schistosomiasis

<b>Background</b><b></b>Schistosomiasis or bilharzia is a parasitic disease caused by trematode flatworms of the genus <i>Schistosoma</i>. Infection of <i>S</i>.<i> mansoni</i> in humans results when cercariae emerge into the water from freshwater snails in the genus <i>Biomphalaria</i>, and seek out and penetrate human skin. The snail <i>B. straminea</i> is now present at several locations in southern China, and represents a potential reservoir for spreading schistosomiasis. To date, genomic information for the species is only available for the species <i>B. glabrata</i>, which<i> </i>mainly inhabits Central and South America. This hinders understanding of the biology and management of other important schistosomiasis vectors, such as <i>B. straminea</i>.<b>Findings</b><b></b>Using a combination of Illumina short‐read, 10X Genomics linked‐read, and Hi‐C sequencing data, our 1.005 Gbp <i>B. straminea</i> genome assembly is of high physical contiguity, with a scaffold N50 of 25.3 Mbp, and high completeness with 87.0% BUSCO score. Developmental homeobox genes, hormonal genes, and stress-response genes were also identified. Comparisons with other mollusc genomes revealed syntenic conservation, dynamic expansion of heat shock protein genes, and the presence of sesquiterpenoid and cholesterol in certain lineages among mollusc diversity.<b>Conclusion</b><b></b>This study provides the first genome assembly for snail <i>Biomphalaria</i> <i>straminea</i> and provides an unprecedented opportunity to address a variety of evolutionary, genomic, and disease questions relating to molluscs more widely.