Question

Name and explain the technique used in the separation and isolation of DNA fragments to be used in recombinant DNA technology...?​

Answer 1

Answer:

Techniques used in recombinant DNA  

 

Fig. 39.1. A gel with electrophoresed DNA in several lanes.

Separation of DNA fragments using agarose or poiyacrylamide gel electrophoresis. When genomie DNA, extracted from any tissue of a plant or animal species, is digested with a restriction enzyme, it is cleaved into segments. The, segments of different sizes can be separated through gel electrophoresis before a molecular probe is used to detect the segments which have sequences similar to those in the probe (for molecular probes, see later in this section). Gel electrophoresis involves movement of fragments or molecules under a well created on one edge of the gel. The gel may be a cylinder or a slab (usually a slab for cloning expt.), about 10 cm long and 0.5 cm thick. The rate of movement of fragments is inversely correlated with the size of fragments or molecules, so that heavier fragments will remain closer to the site of loading and the lighter fragments will move away (Fig. 39.1). Fragments of different sizes will appear as bands on the gel and can be examined or isolated for further study. More often agarose gels are used, but for separation of fragments differing by few base pairs, polyacrylamide gels are used. Polyacrylamide gels are more commonly used for DNA sequencing experiments

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