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Genomic DNA samples isolated from plants were compared with viral and plasmid DNAs.

The resolving power of the 0.8% agarose gel is in the range of 10,000 base pairs to 400 base pairs. This means that anything larger than 10kb will all appear pretty much the same size.

This is a realcolor image of an Ethidium Bromide stained gel viewed through a UV lamp transilluminator. The blue and violet bands that run across several lanes are the sample marker dyes, bromothymol blue and xylene cyanol.

Of the total (uncut) DNA samples, only the plasmid DNA is small enough to be resolved in the gel. When the viral (lambda) DNA is cut with a restriction enzyme, the particular enzyme cuts the DNA into several different fragments, most of which can be resolved in this gel.

The appearance of the plant DNA lanes indicates that the preparations are good quality. The lanes show only slight smearing, indicating that most of the DNA is quite large and unbroken. The intense bands of RNA also indicate high quality DNA. RNA tends to self-destruct. It is very unstable. The presence of RNA does not interfere with most DNA studies.