Question

In the given pedigree chart, ‘P’ is a female suffering from a disease, which is denoted by ‘A’ (dominant allele) and ‘a’ (recessive allele). Find the genotype of ‘P’.

• A. AA
• B. XAX
• C. XAXA
• D. aa

Answer 1

Answer: (D)

aa

Answer 2

Since ‘P’ is affected by a recessive disorder, her genotype must be homozygous recessive (aa) to express the trait, given that a dominant allele ‘A’ would mask the expression if present. Thus, for a recessive disorder, the affected individual would display the trait only if they are homozygous recessive (aa).