In the given pedigree,indicate whether the shaded symbols indicate a dominant or recessive allele.

Of a normal couple,half the sons are haemophilic while half the daughters are carriers. The gene is located on $:-$

Why are some genetic disorders not eliminated from the gene pool despite being harmful?

Mental retardation in children suffering from galactosemia can be avoided by

The harmful allele of sickle cell anemia has not been eliminated from the human population. Such afflicted people derive some other benefit. Discuss.

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?