Most studies on human genetics have been made through

Phenylketonuria $(PKU)$ is an inborn error of metabolism caused by the expression of recessive genes $(pp)$. In this condition,the amino acid phenylalanine is not converted into which amino acid,and what type of genetic disorder is it?

Write a short note on Haemophilia.

Which of the following genotypes causes sickle cell anemia?

$A$ normal woman,whose father was color-blind,marries a normal man. What will be the status of their sons?

Mr. Stevan is suffering from haemophilia and cystic fibrosis. His father is heterozygous for cystic fibrosis. The probability of Stevan's sperm having recessive $X$-linked as well as autosomal allele is