BRAINCAKESouthern Blotting and Gene Probes
After gel electrophoresis the DNA bands cannot be seen, and the soft gel is hard to handle. Southern blotting transfers the DNA from the gel onto a membrane so specific fragments can be located with gene probes.
Method
1. The gel is soaked in an alkaline solution. This denatures the DNA, separating it into single strands so a probe can bind later.
2. A nylon membrane is placed on the gel, with layers of absorbent paper on top. Solution is drawn up through the gel by capillary action, carrying the DNA fragments onto the membrane. The fragments keep the same positions they had in the gel, so the membrane is an exact copy of the pattern.
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Key terms in this lesson
- complementary base pairing
- The pairing of DNA or RNA bases according to fixed rules (A with T or U, C with G) by hydrogen bonding.
More in Gene Sequencing
- DNA Sequencing
- Using DNA Sequencing
- Using DNA Sequencing to Manage Disease
- Introns and Satellite DNA
- DNA Profiles
- Gel Electrophoresis
- Forensic Science
- Paternity Testing
All 12 lessons in Gene Sequencing · All Edexcel A-level Biology topics