(a) Cloning of genes, play a very significant role in genetic engineering, helping the transfer of desirable foreign genes into different hosts. The…

Cloning of genes, play a very significant role in genetic engineering, helping the transfer of desirable foreign genes into different hosts. The scientists, to make this process easier and effective are creating engineered vectors in such a way that they help easy linking of foreign DNA and selection of recombinants from non recombinants. 'pBR322' is one such engineered vectors developed by scientists. A diagram of an engineered vector pBR322 is given below :

Name the host for this cloning vector.

Identify 'Rop' and 'Ori' in the diagram from 'U', 'V', 'W', 'X', 'Y' and 'Z'. Write their functions.

Draw the fragments that will be formed by the action of 'Z' (marked in the diagram) on the specific site of the DNA segment given below : \[\begin{aligned} & \text { 5' --- GTACGAATTCCTGA---3' } \\ & \text { 3'---CATGCTTAAGGACT---5' } \end{aligned} \]

RNA interference (RNAi) holds great potential as a therapeutic agent for the treatment of human diseases and as biocontrol agents in controlling pests in the field of agriculture. An experiment was carried to study the use of 'RNAi' for the potential treatment of disorders of cholesterol metabolism. Some people possess genetic mutations with elevated levels of ApoB gene which predisposes them to coronary artery diseases. Lowering the amount of ApoB can reduce the number of lipoproteins and lower the blood cholesterol. Tracy Zimmerman and her colleagues used RNAi in $\displaystyle 2006$ to reduce the level of ApoB in non human primates Cynomolgus monkeys. One group of monkeys were given RNAi treatment (small interfering RNAs, SiRNAs) (doses $\displaystyle 1$ mg/kg SiRNAs), second group of monkeys were given RNAi treatment (doses $\displaystyle 2.5$ mg/kg SiRNAs) and third group of monkeys were injected with saline. The results of the study are depicted in the graph below :

How does the treatment with $\displaystyle 2.5$ mg/kg brings an effect on cholesterol metabolism when compared from $\displaystyle 24$ hours and $\displaystyle 144$ hours.

Write any two natural sources from where dsRNA molecule could be obtained for silencing the specific mRNA.

How is RNAi used in controlling the infection on the roots of tobacco plants by the nematode Meloidogyne incognitia.