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🔬 Biology  ·  Biotechnology: Principles and Processes  ·  NEET

The CRISPR prime editing system (Liu lab, 2019) improves upon base editing by:

Answer: Using a pegRNA + Cas9 nickase + reverse transcriptase to install any base change, small insertions or deletions without DSB and without a DNA donor template.

  • A Generally using somewhat longer guide RNA molecules in order to improve overall on-target editing specificity each time as widely reported in standard practice
  • B Using a pegRNA + Cas9 nickase + reverse transcriptase to install any base change, small insertions or deletions without DSB and without a DNA donor template
  • C Requiring an exogenous DNA donor template to be supplied alongside most genome edit that is made consistently under most conditions encountered as frequently observed in practice
  • D Working mainly on C to T base conversions, much like standard first-generation base editing tools generally in many documented cases according to conventional understanding

Correct answer: B. Using a pegRNA + Cas9 nickase + reverse transcriptase to install any base change, small insertions or deletions without DSB and without a DNA donor template

Explanation: Prime editing: pegRNA (guide RNA + desired edit sequence). Cas9 nickase nicks one strand; reverse transcriptase uses pegRNA template to write new sequence. Highly versatile, no DSB.

PlasmidGene of interestcutrestriction enzymeligateRecombinantplasmidHost cell

Recombinant DNA technology: a gene of interest and plasmid are cut by the same restriction enzyme, ligated into a recombinant plasmid, and introduced into a host cell.

Concept context

Recombinant DNA, GMOs, PCR, CRISPR, and biotechnology applications. Growing importance in NEET.

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