The DNA size marker is a commercial 1 kbp ladder. The position of the wells and direction of DNA migration is noted. Agarose gel is easy to cast, has relatively fewer charged groups, and is particularly suitable for separating DNA of size range most often encountered in laboratories, which accounts for the popularity of electrophoresis of proteins pdf use.
The separated DNA may be viewed with stain, most commonly under UV light, and the DNA fragments can be extracted from the gel with relative ease. Most agarose gels used are between 0. The 3-D structure is held together with hydrogen bonds and can therefore be disrupted by heating back to a liquid state. Low-melting and low-gelling agaroses made through chemical modifications are also available. Agarose gel has large pore size and good gel strength, making it suitable as an anticonvection medium for the electrophoresis of DNA and large protein molecules. Agarose gel has lower resolving power than polyacrylamide gel for DNA but has a greater range of separation, and is therefore used for DNA fragments of usually 50-20,000 bp in size.