The gene for colour blindness is carried by:

In pedigree analysis,the symbol given for sex unspecified is

Assertion: Phenylketonuria is an autosomal recessive hereditary disease caused by the body's failure to oxidize the amino acid $phenylalanine$ to $tyrosine$ due to a defective enzyme.
Reason: It results in the accumulation of $phenylpyruvic$ acid and its derivatives in the urine.

If both parents are carriers of thalassemia,which is an autosomal recessive disorder,what is the probability of having an affected child?

If a man who is colour blind marries a woman who is pure normal for colour vision,the chances of their sons having colour blindness is

Explain thalassemia.