F9 and hemophilia B: This makes them valuable for studying conditions such as hemophilia B, where accurate modeling of blood volume and coagulation pathways is critical [3].By employing the CRISPR/Cas9 system, Chen et al. created a porcine model by knocking in the human Factor IX gene into pigs, which allowed for the detailed study of bleeding patterns and therapeutic gene integration, showing partial success in reducing bleeding tendencies [56].