KCET2026BiologyPrinciples of Inheritance and Variation
In a practical examination, the below given pedigree chart was given as spotter for identification. The students identified the pedigree chart as ____
Options
- AAutosomal recessive
- BAutosomal dominant
- CSex-linked dominant
- DSex-linked recessive
Correct answer
B. Autosomal dominant
Step-by-step solution
If the trait were sex-linked recessive, the affected mother in generation I would have only affected sons. Since she has an unaffected son in generation II, it is not sex-linked recessive. The trait appears in all generations, indicating a dominant trait. Assuming it is autosomal dominant, let the affected allele be A and the normal allele be a . The affected female in generation I must be heterozygous ( Aa ) because she has unaffected offspring ( aa ). Her unaffected partner is aa . The cross Aa aa produces both a