Explain gene editing
Describe targeted insertion, deletion or replacement of DNA as gene editing.
A Level; Cambridge International Biology 9700, 2028–2030. This is curriculum teaching, not medical advice or a claim that a treatment is suitable for an individual. Written responses are self-checked
Before you begin
- DNA stores genetic information; genes can be expressed to produce RNA and protein.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which three DNA changes define gene editing here?
What you will learn
- Define gene editing as targeted DNA change
- Distinguish insertion, deletion and replacement at a specific site
Build the explanation
Gene editing is a form of genetic engineering that inserts, deletes or replaces DNA at specific sites in the genome. The target is a chosen genomic region, so the intended change is more localised than adding DNA at an unspecified position. Edited cells must be checked to confirm the intended sequence change.
Use the evidence carefully
Targeted does not mean error-free or automatically safe. Editing can have unintended changes, and a sequence change may not produce the predicted phenotype. Specify what was changed and how the result was verified.
Pause and explain
Why must edited cells be checked after the procedure?
Worked example
A nucleotide sequence is replaced at a selected genomic site. Which category of change is this?
Show the worked solution
- The original DNA at a specific site is substituted.
- It is replacement.
Answer Replacement of DNA at a specific genomic site.
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Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A short DNA sequence is removed from a selected genome site. Name the type of edit.
Give me a hint
Identify the relevant material or technology and explain each step.
Compare my reasoning
- DNA is removed.
- This is deletion.
Deletion: the DNA sequence is removed from the specified genome site.
Look for these in your work
- Method identified
- Steps linked to function
A new sequence is added at a chosen site. Which type of gene edit is described?
Give me a hint
Use the stated example to justify a conclusion.
Compare my reasoning
- DNA is added.
- This is insertion.
Insertion: a DNA sequence is added at the selected genome site.
Look for these in your work
- Evidence interpreted
- Limits stated
Why must edited cells be checked after the procedure?
Give me a hint
Apply the idea to a new application or trade-off.
Compare my reasoning
- The intended edit may not occur in every cell.
- Unintended changes may also occur.
Verification is needed to confirm the intended sequence change and assess whether unintended edits occurred.
Look for these in your work
- Application explained
- Claim appropriately bounded
Common mistakes
- Calling every gene transfer gene editing
- Claiming target selection means no off-target changes
What can you explain now?
Which three DNA changes define gene editing here?
Compare with the explanation
Insertion, deletion or replacement
The change is made at a specific genome site.
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Make it stick
How does targeted gene editing differ from inserting a gene without a chosen site?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.