Four chromosome-scale ampullariid genomes: high-quality resources for ecological, evolutionary, and invasion biology studies.

The New World Ampullariids, encompassing the ecologically important genera Pomacea and Marisa, are gastropods with dual attributes-serving as model systems for evolutionary and environmental research while posing severe threats as globally invasive species. Here, we present chromosome-scale genomes of four key species-Pomacea canaliculata, P. maculata, P. diffusa, and Marisa cornuarietis-generated through PacBio HiFi sequencing and Hi-C scaffolding. These assemblies exhibit exceptional continuity and completeness (BUSCO scores > 95%) with genome sizes ranging 450-540 Mb, while high-quality annotations predicting 21,687-22,481 protein-coding genes per genome. Comparative analysis reveals divergent genome architectures: the invasive P. canaliculata and P. maculata harbour lower LINE (5.7-5.8%) and LTR (0.7-0.8%) content compared to non-invasive P. diffusa (LINE: 7.7%; LTR: 0.8%) and M. cornuarietis (LINE: 9.5%; LTR: 1.1%), suggesting repeat dynamics linked to ecological plasticity. Macrosynteny analyses identify five dynamic but conserved ancestral chromosomal fusions across species but with limited rearrangements among species. These resources, integrating chromosomal resolution with functional annotation, provide a foundation for comparative studies on molluscan karyotype evolution and adaptive radiation research, as well as possible targets for CRISPR-cas9-driven biocontrol strategies.