Govt. Exams
Entrance Exams
High-fidelity Cas9 variants (eSpCas9, SpCas9-HF1) with stringent guide RNA design using prediction tools significantly reduce off-target cleavage in therapeutic applications.
Each zinc finger domain recognizes approximately 3 bp. Three domains recognize 9 bp, which provides adequate specificity for most genomic targets.
Prime editing fuses Cas9 nickase with reverse transcriptase, allowing creation of diverse genetic modifications from a single RNA template without creating double-strand breaks, offering superior precision and safety.
Base editors convert one nucleotide to another without creating double-strand breaks, but optimizing specificity to edit only intended bases while avoiding unintended modifications remains a significant hurdle.
Pooled CRISPR screening uses large libraries of guide RNAs to simultaneously test thousands of genetic perturbations, allowing identification of genes associated with specific phenotypes through NGS readout.
RNAi uses small interfering RNAs (siRNAs) that guide the RNA-Induced Silencing Complex (RISC) to degrade specific target mRNAs, effectively silencing gene expression post-transcriptionally.
Germline (heritable) editing raises profound ethical, religious, and social concerns about modifying the human genome permanently. Most countries, including India, have strict regulations or moratoriums on germline editing applications.
The spread of herbicide or insect resistance genes to wild relatives creates organisms that are difficult to control and can disrupt ecosystems. This is the primary biosafety concern in several regulatory assessments, particularly for herbicide-resistant crops.
Ex vivo gene therapy involves editing cells outside the body, allowing for rigorous selection of successfully modified cells and quality control before reimplantation. This reduces risks associated with unsuccessful edits.
Comprehensive environmental impact assessment requires multi-generational studies examining effects on biodiversity, soil health, water systems, and non-target organisms. Short-term yield data alone is insufficient for determining ecological safety.
