•The northern blot is used to study the expression patterns of a specific type of RNA molecule as relative comparison among a set of different samples of RNA.
•RNA is separated based on size and is then transferred to a membrane then probed with a labeled complement of a sequence of interest.
•The results may be visualized through a variety of ways depending on the label used. Most result in the revelation of bands representing the sizes of the RNA detected in sample.
•The intensity of these bands is related to the amount of the target RNA in the samples analyzed.
•It is used to study when and how much gene expression is occurring by measuring how much of that RNA is present in different samples.
•one of the most basic tools for determining at what time, and under what conditions, certain genes are expressed in living tissues.