Researchers have successfully achieved heritable genome editing in C. elegans using a CRISPR-Cas9 system. The study describes the use of Cas9 and single-guide RNAs (sgRNAs) to target and modify specific genes in the germline, enabling the generation of loss-of-function mutants. The sgRNAs were expressed from a U6 small nuclear RNA promoter, ensuring efficient and targeted gene disruption. The system was tested on the unc-119 and dpy-13 genes, which are known to cause visible phenotypes when disrupted. The results showed that targeted mutations could be inherited, demonstrating the potential of CRISPR-Cas9 for heritable genome editing in C. elegans. The CRISPR-Cas system is an adaptive defense mechanism in bacteria and archaea that allows them to recognize and destroy viral DNA. The system uses CRISPR RNA (crRNA) and a Cas endonuclease to target and cleave specific DNA sequences. Recent advancements have enabled the use of a single guide RNA (sgRNA) that combines the functions of crRNA and trans-activating crRNA (tracrRNA), allowing for efficient and precise genome editing in various organisms, including yeast, Drosophila, human and mouse cells, and zebrafish and mice. In this study, the researchers developed vectors to express Cas9 and sgRNAs in the C. elegans germline. They used a U6 snRNA promoter to drive sgRNA expression, which was chosen for its effectiveness in the germline. The sgRNAs were designed to target specific sequences in the genome, with a specific protospacer-associated motif (PAM) at the end of the target sequence. The system was tested on the unc-119 and dpy-13 genes, and the results showed that targeted mutations could be inherited, indicating the potential of CRISPR-Cas9 for heritable genome editing in C. elegans. The study also demonstrated the ability to generate mutations in genes that do not cause visible phenotypes. The researchers targeted two additional genes, klp-12 and Y61A9LA.1, and successfully generated mutations in these genes. The mutations were confirmed through sequencing and restriction enzyme analysis, showing that the CRISPR-Cas system can be used to generate a wide range of genetic modifications in C. elegans. The study also assessed the specificity of the CRISPR-Cas system, searching for potential off-target effects. The results showed no evidence of off-target cleavage, indicating that the system is highly specific. The researchers concluded that the CRISPR-Cas system has great potential for heritable genome editing in a wide variety of multicellular eukaryotes.Researchers have successfully achieved heritable genome editing in C. elegans using a CRISPR-Cas9 system. The study describes the use of Cas9 and single-guide RNAs (sgRNAs) to target and modify specific genes in the germline, enabling the generation of loss-of-function mutants. The sgRNAs were expressed from a U6 small nuclear RNA promoter, ensuring efficient and targeted gene disruption. The system was tested on the unc-119 and dpy-13 genes, which are known to cause visible phenotypes when disrupted. The results showed that targeted mutations could be inherited, demonstrating the potential of CRISPR-Cas9 for heritable genome editing in C. elegans. The CRISPR-Cas system is an adaptive defense mechanism in bacteria and archaea that allows them to recognize and destroy viral DNA. The system uses CRISPR RNA (crRNA) and a Cas endonuclease to target and cleave specific DNA sequences. Recent advancements have enabled the use of a single guide RNA (sgRNA) that combines the functions of crRNA and trans-activating crRNA (tracrRNA), allowing for efficient and precise genome editing in various organisms, including yeast, Drosophila, human and mouse cells, and zebrafish and mice. In this study, the researchers developed vectors to express Cas9 and sgRNAs in the C. elegans germline. They used a U6 snRNA promoter to drive sgRNA expression, which was chosen for its effectiveness in the germline. The sgRNAs were designed to target specific sequences in the genome, with a specific protospacer-associated motif (PAM) at the end of the target sequence. The system was tested on the unc-119 and dpy-13 genes, and the results showed that targeted mutations could be inherited, indicating the potential of CRISPR-Cas9 for heritable genome editing in C. elegans. The study also demonstrated the ability to generate mutations in genes that do not cause visible phenotypes. The researchers targeted two additional genes, klp-12 and Y61A9LA.1, and successfully generated mutations in these genes. The mutations were confirmed through sequencing and restriction enzyme analysis, showing that the CRISPR-Cas system can be used to generate a wide range of genetic modifications in C. elegans. The study also assessed the specificity of the CRISPR-Cas system, searching for potential off-target effects. The results showed no evidence of off-target cleavage, indicating that the system is highly specific. The researchers concluded that the CRISPR-Cas system has great potential for heritable genome editing in a wide variety of multicellular eukaryotes.