Studyledge

Genetic Technology: Question 4

Syllabus 19.2

Multiple choice A2 1 mark

Which statement correctly distinguishes genetic screening from gene therapy?

Choose an answer to check it, then compare with the worked solution below.
Show worked solution Hide worked solution

Worked solution

Working through the options

Genetic screening and gene therapy both feature in the medical applications of genetic technology, but they do very different jobs, and exam questions often test whether this distinction is clear.

Genetic screening is a diagnostic technique: it involves testing a sample of a person’s DNA to find out whether they carry a particular disease-associated allele. It does not change anything in the person’s cells; it simply provides information, for example about the risk of developing breast cancer (linked to the BRCA1 and BRCA2 genes), Huntington’s disease, or cystic fibrosis.

Gene therapy is a treatment: it involves inserting a working (functional) copy of a gene into the cells of a person who has, or is at risk of, a genetic disease caused by a faulty gene, so that the functional gene can be expressed. Examples include treating severe combined immunodeficiency (SCID) and some inherited eye diseases.

Checking each option:

  • A, correctly describes genetic screening as diagnostic (identifying a disease-associated allele) and gene therapy as inserting a functional gene to treat disease. Correct.
  • B, reverses the two definitions; incorrect.
  • C. Screening does not involve inserting a gene at all, so this option is incorrect on that point alone.
  • D. Both techniques can, in principle, be used at more than one life stage; this option is too restrictive and incorrect.

Final answers

  • A, genetic screening identifies whether a person carries a disease-associated allele; gene therapy treats a genetic disease by inserting a functional gene.