Chapter 20, Problem 18EQ

Summary Introduction

To analyze:

Southern blotting is a technique used to detect the target gene sequence within a mixture of several genes.

In an experiment, Gene X from corn is cloned. From this clone, the labeled DNA strand is used to make a probe for genomic DNA, and the stringency of the probe to the genomic DNA, under high and low conditions, were tested on southern blotting. The following results were obtained: What do the results depict about stringency?

Introduction:

Southern blotting is a technique used to detect the target gene sequence within a mixture of several genes. This method was introduced by Edwin Southern in $1975$.

The goal of southern blotting is to detect if a sample of the genome contains a complementarity with the specific probe.

In this technique, first, the genomic DNA is isolated followed by the digestion of Restriction enzymes that results in the production of several fragments. These fragments are separated on gel electrophoresis according to their masses. Later, the DNA is blotted onto a nylon membrane; this ensures that the DNA is bound to the membrane. This membrane is incubated and labeled; probes are introduced with the unlabeled genomic DNA in a solution.

If there is complementarity with labeled probe and unlabeled DNA, then it will show a band on the gel.

The major variables in southern blotting are temperature and ionic strength of hybridization.