Question

pt) Hemochromatosis is a condition in which excess iron is stored in the liver, pancreas, and skin. The condition in humans is controlled by a single gene, the allele for hemochromatosis being recessive. A normal boy whose parents are normal has one affected grandparent. If none of the other grandparents carry the allele for hemochromatosis, what is the probability that the boy is heterozygous for this allele? 3.

Answer 1

The grandparent is homozygous for the recessive allele the probability is 1/2 (0.5)

Step-by-step explanation:

You need to know what's the probability for the parents to carry the allele, and then know the probability of the child to carry the allele. Then you multiply both probabilities. Now, how do you know the probabilities?: Punnett square.

1. For the grandparent is homozygous for the recessive allele:

The probability for a parent is 1 (AA*aa= every child will be Aa 'hetherozygous')

Now, as a parent is Hetherozygous and the other don't, the probability for a child in here is 1/2 (AA*Aa= 1/2Aa + 1/2AA)

When you multiply both probabilities is 1/2 or 0.5