Define the term ‘carrier’ in genetics and illustrate it with a specific example of an autosomal recessive disorder.
Answer
A carrier is an individual who possesses one normal allele and one mutant allele (heterozygous) and does not show the disease; e.g., a person with genotype Aa for sickle‑cell anemia, where A is normal and a causes sickle cells.
Step-by-step solution
- State that a carrier has one dominant (normal) allele and one recessive (mutant) allele.
- Explain that the dominant allele masks the effect of the recessive allele, so the carrier is phenotypically normal.
- Give a concrete example: sickle‑cell anemia where the normal allele is A and the disease allele is a; a carrier is Aa.
- Mention that such carriers can pass the recessive allele to offspring.
Common mistake: Thinking that a carrier shows symptoms of the disease.
Concept tested: Carrier concept in autosomal recessive inheritance
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Related questions
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