Question

Study the given pedigree chart in which neither of the parents shows the trait but the trait is present in both male and female children.

Write about the trait, also explain the inheritance of such a trait in the progeny on the basis of the given pedigree chart.

Hint:

In autosomal recessive inheritance, both parents must be carriers of the recessive allele for the trait to be expressed in the offspring. Affected individuals inherit one recessive allele from each parent.

Answer 1

Analyzing the Pedigree Chart and Inheritance Pattern 

Step 1: Analyzing the Pedigree Chart

- In the pedigree chart, neither of the parents shows the trait (as both the father and mother are represented without filled circles or squares). 
- However, both the male and female children (represented by filled circles and squares) show the trait. 
- This suggests that the trait is recessive in nature. Both parents are carriers of the trait (heterozygous) and pass it on to the offspring.

Step 2: Explanation of the Inheritance Pattern

- The trait is inherited in a recessive manner, and both parents must be carriers of the recessive allele (genotype Aa) for the trait to be expressed in their children. 
- Since the trait is expressed in both male and female children, this suggests autosomal inheritance.

Step 3: Conclusion

- The parents are carriers of a recessive allele (genotype Aa), and the trait is autosomal recessive. The children inherited the recessive allele from both parents (genotype aa), resulting in the expression of the trait.