The correct sequence of steps to obtain gene of interest from pool of…

The correct answer is Option (1) → A, C, E, B, D

A. Cutting of DNA using restriction endonuclease — first. The enzyme cuts the DNA into fragments of different sizes.

C. Loading of DNA in wells — second. The digested DNA is put into the wells of an agarose gel.

E. Separation of DNA fragments according to their molecular size — third. In an electric field the negatively charged DNA moves towards the anode; smaller fragments move farther through the gel.

B. Viewing the ethidium bromide stained gel under UV light — fourth. DNA cannot be seen directly; after staining it shows as bright orange bands in UV light.

D. Cutting and extraction of DNA piece from gel — last. The band holding the gene is cut out and the DNA is extracted (elution), ready for joining to a vector.

NCERT Extract:
Restriction Enzymes – “… Since DNA fragments are negatively charged molecules they can be separated by forcing them to move towards the anode under an electric field through a medium/matrix. Nowadays the most commonly used matrix is agarose which is a natural polymer extracted from sea weeds. The DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel. Hence, the smaller the fragment size, the farther it moves.”
Restriction Enzymes – “The separated DNA fragments can be visualised only after staining the DNA with a compound known as ethidium bromide followed by exposure to UV radiation (you cannot see pure DNA fragments in the visible light and without staining). You can see bright orange coloured bands of DNA in a ethidium bromide stained gel exposed to UV light (Figure 9.3). The separated bands of DNA are cut out from the agarose gel and extracted from the gel piece. This step is known as elution.”