Agarose for DNA, RNA and Molecular Biology Electrophoresis

Agarose is a purified polysaccharide used to form porous gels for separating nucleic acids and, in specialized formats, other biomolecules. They are commonly used for DNA fragment separation, RNA quality checks, restriction analysis, PCR verification, gel extraction and preparative electrophoresis. The exact product should be selected according to the target, sample type, workflow and downstream analysis.

Start with the experimental endpoint and sample constraints, then compare molecular biology grade, gel strength, electroendosmosis, melting and gelling temperature, supported fragment range, nuclease testing, clarity and pack size. Review the exact protocol and compatibility data rather than assuming products in the same category are interchangeable.

Use clean nucleic acid, an appropriate loading buffer and a gel concentration matched to the expected fragment sizes. Starting-material quality often has a greater effect on final performance than small differences between product formulations.

Incorrect concentration, incomplete dissolution, damaged wells, excessive voltage and unsuitable buffer can distort migration or reduce resolution. Additional causes can include inaccurate pipetting, expired reagents, inappropriate incubation, contamination or measurements outside the validated range.

Use negative and positive controls appropriate to the workflow, reagent blanks where relevant and a known reference material or sample. Include technical replicates and independent quality checks when the result supports an important conclusion.

Not automatically. Formulation, enzyme activity, binding chemistry, target coverage and buffer composition can change performance. Revalidate critical metrics before switching products in an established study.

Store dry agarose tightly closed and protected from moisture according to the product instructions. Prepared gels and solutions have more limited stability and should be handled with contamination and microbial growth in mind.

Higher concentrations create smaller pores and improve separation of smaller fragments, while lower concentrations favor larger DNA. Very low gels are fragile, and very high gels can slow migration and increase run time.