Study the pedigree chart given below What does it show?

Study the pedigree chart given below What does it show?
  1. Inheritance of a sex-linked inborn error of metabolism like phenylketonuria
  2. Inheritance of a condition like phenylketonuria as an autosomal recessive trait
  3. The pedigree chart is wrong as this is not possible
  4. Inheritance of a recessive sex-linked disease like haemophilia

Solution

In the given pedigree chart, squares are representing males and circles females. In $\mathbf{F}_1$ generation, 1-male and 1-female are diseased and in next generation only male is diseased. This shows the inheritance of a recessive sex-linked disease.

Asked in: NEET 2009 (Screening)

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