Researchers at UC Santa Cruz developed a method to edit the genome of Caenorhabditis elegans using CRISPR-Cas9 and homologous recombination. This technique allows precise modification of the genome, enabling the creation of targeted mutations and gene knock-ins. The study demonstrated that Cas9 can induce DNA double-strand breaks at specific sites, which can be efficiently repaired by homologous recombination. This approach provides a flexible and cost-effective method for genome modification in C. elegans, expanding the range of genetic manipulations possible. The method was tested on various genes, including nmy-2 and his-72, where gfp was successfully inserted into endogenous loci without affecting gene function. The study also showed that Cas9-triggered homologous recombination can be used to generate multiple point mutations in a single step, as demonstrated with the lin-31 gene. The technique was found to be highly specific, with no off-target mutations detected. The study highlights the potential of CRISPR-Cas9 for genome editing in C. elegans, offering a powerful tool for genetic research. The method is robust, efficient, and applicable to a wide range of genetic modifications, making it a valuable addition to the genetic tools available for this model organism.Researchers at UC Santa Cruz developed a method to edit the genome of Caenorhabditis elegans using CRISPR-Cas9 and homologous recombination. This technique allows precise modification of the genome, enabling the creation of targeted mutations and gene knock-ins. The study demonstrated that Cas9 can induce DNA double-strand breaks at specific sites, which can be efficiently repaired by homologous recombination. This approach provides a flexible and cost-effective method for genome modification in C. elegans, expanding the range of genetic manipulations possible. The method was tested on various genes, including nmy-2 and his-72, where gfp was successfully inserted into endogenous loci without affecting gene function. The study also showed that Cas9-triggered homologous recombination can be used to generate multiple point mutations in a single step, as demonstrated with the lin-31 gene. The technique was found to be highly specific, with no off-target mutations detected. The study highlights the potential of CRISPR-Cas9 for genome editing in C. elegans, offering a powerful tool for genetic research. The method is robust, efficient, and applicable to a wide range of genetic modifications, making it a valuable addition to the genetic tools available for this model organism.