[2026] PTE Academic Reading - Multiple Choice, Multiple Answers

CRISPR-Cas9 is a groundbreaking technology that allows scientists to edit parts of the genome by removing, adding, or altering sections of the DNA sequence.This system is derived from a naturally occurring genome editing mechanism found in bacteria, which use it as an immune response against invading viruses.By utilizing a guide RNA to target a specific DNA sequence and the Cas9 enzyme to act as molecular scissors, researchers can make precise modifications with unprecedented ease.One of the most significant advantages of CRISPR over earlier gene-editing techniques is its cost-effectiveness and high level of efficiency.However, the technology is not without its limitations, as unintended 'off-target' effects can occur when the Cas9 enzyme cuts the DNA at sites similar to the target sequence.These off-target mutations pose potential risks, including the disruption of essential genes or the inadvertent activation of oncogenes.Furthermore, the ethical implications of germline editing—modifying DNA in human embryos—remain a subject of intense global debate.Proponents argue that it could eliminate hereditary diseases, while critics fear the long-term impacts on the human gene pool and the potential for 'designer babies.'