Question

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

	Column I		Column II
A.	Turners syndrome	(i)	Trisomy
B.	Linkage	(ii)	AA + XO
C.	V-chromosome	(iii)	Morgan
D.	Downs syndrome	(iv)	TDF

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

Answer 1

Answer: (D)

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

Turner syndrome is due to a chromosomal abnormality in which all or part of one of the X chromosomes is missing or altered. While most people have 46 chromosomes, in this condition they usually have 45 (AA+XO). Morgan and his group observed in Drosophila that the proportion of recombinants varies, even if the two genes are present on the same chromosome. They attributed this due to physical association of the two genes and coined the term ‘linkage’. The Y chromosome carries the testes determining factor. Down syndrome also known as trisomy 21, is a genetic disorder caused by the presence of all or part of the third copy of chromosome 21.

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