The CRISPR-Cas system is an adaptive immune mechanism in prokaryotes that has revolutionized genome editing technology in the field of biotechnology. Originally a natural defense against viruses in bacteria, the CRISPR-Cas system has been developed into a versatile tool widely used in gene editing, gene regulation, and disease detection. This review summarizes the molecular mechanisms by which the CRISPR-Cas system identifies and attacks foreign DNA, focusing on its three key steps: adaptation, expression, and interference. Cas9, Cas12, and Cas13 from Type II systems have become mainstream tools in current biotechnology due to their simple structure and diverse functions. This paper also focuses on a newer Cas protein, Cas14, which is small and capable of recognizing single-stranded DNA, showing great potential in the development of high-precision diagnostic tools. Beyond basic research, CRISPR technology has been widely applied in agricultural improvement, disease treatment, and synthetic biology. However, off-target risks, delivery challenges, and ethical issues remain major obstacles to its clinical adoption. Additionally, the paper emphasizes the integrated application of artificial intelligence in optimizing CRISPR systems and stresses the necessity of establishing rigorous ethical governance frameworks. By evaluating fundamental mechanisms and frontier applications, this paper highlights the importance of discovering new Cas proteins and advancing CRISPR technology for future therapeutic and industrial applications.
I Wang (Wed,) studied this question.