Question

Match column I with column II and select the correct option from the given codes.

	Column I		Column II
A.	Autosomal recessive trait	(i)	Downs syndrome
B.	Sex-linked recessive trait	(ii)	Phenylketonuria
C.	Metabolic error linked to autosomal recessive trait	(iii)	Haemophilia
D.	Additional 21st chromosome	(iv)	Sickle cell anaemia

• A. A-(ii), B-(i), C-(iv), D-(iii)
• B. A- (iv), B- (i), C- (ii), D- (iii)
• C. A-(iv), B-(iii), C-(ii), D-(i)
• D. A-(iii), B-(iv), C-(i), D-(ii)

Answer 1

Answer: (C)

A-(iv), B-(iii), C-(ii), D-(i)

Sickle-cell disease is caused by a gene mutation that leads to the production of Sickle hemoglobin, which affects the function of the red blood cells in the body. This mutation is inherited from the parents of an individual in an autosomal recessive pattern which indicates that the mutation is in the autosomal chromosome and will manifest when both the copies of the recessive allele is present. Hemophilia A and hemophilia B are inherited in an X-linked recessive pattern. The genes associated with these conditions are located on the X chromosome, which is one of the two sex chromosomes. Phenylketonuria is an autosomal recessive disorder, caused by mutations in both alleles of the gene for phenylalanine hydroxylase (PAH), found on chromosome 12 and is a condition in which your body can't break down an amino acid called phenylalanine into tyrosine (metabolic error). Down syndrome is usually caused by an error in cell division called “nondisjunction.” Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two.

So, the correct option is 'A-(iv), B-(iii), C-(ii), D-(i)'.