CRISPR/Cas Systems: Biological Basis and Genome Editing Applications

Clustered regularly interspaced short palindromic repeats (CRISPR) and associated (Cas) systems have revolutionized the field of genome engineering by providing versatile, efficient, and programmable tools for precise genetic manipulation. Originally identified as an adaptive immune mechanism in prokaryotes, CRISPR/Cas systems have been extensively repurposed for a wide range of applications across molecular biology, biotechnology, and medicine. This chapter provides a comprehensive overview of the molecular mechanisms underlying CRISPR/Cas immunity. Furthermore, the classification of CRISPR/Cas systems into distinct types and subtypes is discussed, highlighting their structural and functional diversity. Advances in genome editing technologies, including CRISPR-mediated knockout, base editing, and prime editing, are explored with an emphasis on their mechanisms and applications. The chapter also examines emerging CRISPR-based platforms for transcriptional regulation, epigenome editing, and RNA targeting, which enable precise and reversible modulation of gene expression without altering genomic DNA. In addition, the transformative impact of CRISPR technologies on functional genomics is addressed, particularly through high-throughput screening approaches that facilitate the identification of gene function and genetic vulnerabilities. CRISPR-based diagnostic tools and therapeutic strategies are also reviewed, underscoring their potential in disease detection and treatment. Despite significant progress, challenges such as off-target effects, delivery limitations, and safety concerns remain critical considerations. Overall, this chapter highlights the expanding capabilities of CRISPR/Cas systems and their growing importance in both fundamental research and clinical applications.