Spot blot: a hybridization assay for specific DNA sequences in multiple samples

Small aliquots of DNA-containing samples from gradient or column fractions are spotted onto agarose plates containing ethidium bromide, and the DNA is visualized qualitatively. After it is overlaid with a thin agarose cover, the DNA is denatured and transferred to nitrocellulose filters for hybridization. This method, called the "spot-blot assay," is particularly convenient when dealing with large numbers of samples.