Govt. Exams
Entrance Exams
Gene targeting uses homologous recombination to introduce specific changes at exact genomic locations, while CRISPR, TALENs, and ZFNs create double-strand breaks that are repaired by non-homologous end joining.
The guide RNA is complementary to the target DNA sequence and directs the Cas9 nuclease to the correct location for DNA cleavage.
BACs can accommodate inserts of 100-300 kb, while cosmids can hold up to 45 kb. For large inserts, BACs are superior to plasmids (typically 15-20 kb) and phagemids.
BioBricks provide standardized interfaces (RFC10 standards) for combining biological parts into systems, enabling composable genetic design, rapid iteration, and community resource sharing.
India's current biosafety framework mandates 2-3 years of phased trials (contained use, limited field trials, then large-scale) before product approval, ensuring thorough risk assessment.
TALENs have been explored for editing CCR5 in HIV therapy, mimicking natural CCR5-Δ32 deletion. This approach shows potential for functional HIV resistance without integration risks.
E. coli lacks proteases and post-translational modification machinery. Proinsulin can fold properly in bacteria; it's then enzymatically cleaved to produce mature, bioactive insulin.
As of 2024, Bt Cotton remains approved, and Bt Chickpea received commercial approval in 2023-24. Golden Rice and herbicide-resistant crops have not been approved in India.
Longer homology arms (typically 1-2 kb) provide greater sequence identity for recombination machinery recognition, increasing efficiency and reducing off-target integration.
India's 2024 strategy prioritizes gene therapy for rare genetic disorders to address unmet medical needs and reduce disease burden in economically disadvantaged populations.
