CRISPR/Cas in sea lamprey: new tools for functional genomics and genetic control

Abstract CRISPR-based gene-editing methodologies are well established in conventional model organisms such as mice ( Mus musculus) , zebrafish ( Danio rerio) , and fruit fly ( Drosophila melanogaster) . Adapting these methods to non-model systems offers ample opportunities to examine genome function and evolution, but also comes with many technical challenges. Here, we review the evolution and use of CRISPR/Cas9 methodologies, alongside emerging techniques such as base editing and prime editing strategies, and outline their potential advantages and limitations. We then compile recent advances in CRISPR applications in the sea lamprey ( Petromyzon marinus ), a jawless vertebrate that has been used extensively to study vertebrate evolution, neural crest development, neuronal regeneration, and programmed genome reorganization. Moreover, this species is subjected to conservation efforts in several European regions, and to intensive management in North America as a devastating invader of the Laurentian Great Lakes. Application of CRISPR/Cas-based approaches in this species is hindered by delivery efficiency, mosaicism, and genomic and life history complexity. We propose strategies addressing these challenges and future directions for potential uses of synthetic gene drives for knocking out ecologically significant traits, such as sex determination and fecundity. Advances in this model highlight the broader roles of CRISPR innovation, including supporting conservation and invasive species management and inferring how jawless vertebrate species survived and thrived to date.