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.

Answer the following questions:

1. Write about the trait, also explain the inheritance of such trait in the progeny on the basis of given pedigree chart.
2. Give one example of such trait in human beings.

Answer 1

1. The pedigree chart indicates that the trait is autosomal recessive. This indicates that in order for a person to exhibit the trait, they need to inherit two copies of the recessive allele, one from each parent. Since neither parent exhibits the feature in this instance, it is likely that they are heterozygous carriers, meaning they have one copy of the dominant gene and one copy of the recessive allele. Because a normal father has an afflicted daughter, the trait is autosomal. According to the figure, there is a 25% probability that an offspring of carriers will inherit two copies of the recessive allele and exhibit the trait.
2. Phenylketonuria is an example of an autosomal recessive trait in humans. Tay-Sachs disease, sickle cell anemia, and cystic fibrosis are other examples.