Question

Match the following of Column I with that of Column II
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{i. Mutagens}& \text{p. Point mutation}\\ \text{ii. Sickle cell anaemia}& \text{q. Virus}\\ \text{iii. Drosophila}& \text{r. XX – XO type}\\ \text{iv. Grasshoppers}& \text{s. Linkage discovery}\end{array}$

• A. i – q, ii –p – iii – r, iv – s
• B. i – q, ii – s, iii – r, iv – p
• C. i – s, ii- p, iii – r, iv – q
• D. i – q, ii –p – iii – s, iv – r

Answer 1

The correct option is D i – q, ii –p – iii – s, iv – r

Mutagens are the agents that can cause alteration in the DNA of an individual. It can be physical, chemical or biological in nature. Certain viruses act as biological mutagens, for example Oncoviruses causing cancer.

Sickle cell anaemia is an autosomal genetic disorder in which Red Blood Cells (RBCs) take up a sickle shape. This defect is due to the substitution of a single base pair (point mutation) which replaces amino acid glutamic acid with valine at the sixth position of the beta-chain of the haemoglobin molecule (Hb).

Morgan carried out several dihybrid crosses in Drosophila and provided experimental evidence for linkage.

In grasshoppers, females are homogametic (XX) and produce ova with X chromosomes, whereas males are heterogametic with one-half of sperms with an X chromosome and the other half with no sex chromosome.