eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2025-09-30 22 3 901 913 10.13005/bbra/3413 56572 article Esha Kumari 1 Neha Banu 2 Kathrina Marbaniang 2 Faridha Jane R.M. Momin 3 Barry Cooper Hynniewta 4 Department of Clinical Embryology, Yenepoya (deemed to be university), Karnataka, India Department of Medicine, Shillong Medical College, Meghalaya, India Department of Oncology, Shillong Civil Hospital, Meghalaya, India Department of Clinical Embryology, MOMSOON Fertility and IVF Centre, Karnataka, India Gene editing exploits endogenous DNA repair pathways to introduce precise modifications into the genome. The CRISPR system was first identified in Escherichia coli (1987) and, based on Cas protein architecture, is divided into Class I (types I, III, IV) and Class II (types II, V, VI). The widely adopted CRISPR/Cas9 system comprises a guide RNA (gRNA) and the Cas9 endonuclease, which orchestrate genome editing through a tripartite mechanism: target sequence recognition via gRNA binding to a complementary DNA site adjacent to a protospacer adjacent motif (PAM), double-stranded DNA cleavage by two nuclease domains (RuvC cleaving the non‑target strand and HNH the target strand), and repair of the resulting break by cellular pathways. This approach has been applied to in vitro fertilization-derived embryos and meiotically developing oocytes to disrupt or correct genes, offering potential for eliminating heritable diseases. However, concerns remain regarding off-target effects that introduces unwanted genetic mutations, necessitating improved specificity and ethical scrutiny. https://www.biotech-asia.org/vol22no3/crispr-cas9-mediated-gene-editing-in-human-gametes-a-review/ CRISPR/Cas9; DNA; Gametes; Gene editing; Infertility