Inheritance of traits in humans is studied by analyzing the presence or absence of a trait in a family. This is then depicted as a chart showing different generations and indicating individuals who show the trait. The following is a pedigree for a rare genetic disorder representing parents (top row) and their three children.
The pedigree suggests that the genetic disorder could be either autosomal recessive or X-linked recessive.
The following statements were made about the genotypes (with respect to the gene responsible for the disorder) of the 5 individuals in this pedigree:
a. The mother is heterozygous.
b. The daughters could be either homozygous or heterozygous.
c. The daughters are only homozygous.
(I) Which of the above statement(s) is/ are correct if the genetic disorder is
i. Autosomal recessive ?
ii. X-linked recessive ?
(II) Assuming that both the parents carry the allele responsible for the disorder, what is the probability that the first daughter would carry the same allele?
(III) Assume that the trait is X-linked recessive. The affected son marries a woman who does not carry the allele for the disorder. When they have a child, what is the probability that child will carry the allele, if the child is a