A Step-by-Step Guide to Gel Extraction for High-Quality DNA/RNA Recovery

gel extraction / gel isolation

technique used to recover nucleic acid fragments of interest from an agarose gel

Gel extraction or gel isolation is a technique used to recover specific fragments of DNA or RNA from an agarose gel following electrophoresis.

Here are the steps for gel extraction/isolation:

1. Excise the desired DNA fragment from the gel: Cut out the band of interest with a clean, sharp razor blade or scalpel. Avoid disturbing or contaminating the gel slice as much as possible.

2. Melt the gel: Transfer the gel slice into a microcentrifuge tube and add a lysis buffer to dissolve the gel. The lysis buffer typically contains a combination of salts and detergents to break down the gel and release the DNA/RNA.

3. Bind the DNA/RNA: Transfer the dissolved DNA/RNA to a spin column containing a silica-based membrane that binds nucleic acids. The DNA/RNA binds to the membrane while impurities such as salts and proteins are washed away.

4. Wash the spin column: The bound DNA/RNA is washed several times with a washing buffer to remove residual contaminants from the sample.

5. Elute the DNA/RNA: Finally, the purified DNA/RNA is eluted from the membrane into a clean microcentrifuge tube using a low-salt buffer or water.

After gel extraction, the DNA/RNA can be used for downstream applications such as PCR, restriction enzyme digestion, sequencing, or cloning.

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