A Neuronal lineage marker is an endogenous tag that is expressed in different cells along neurogenesis and differentiated cells such as neurons. It allows detection and identification of cells by using different techniques. A neuronal lineage marker can be either DNA, mRNA or RNA expressed in a cell of interest. It can also be a protein tag, as a partial protein, a protein or an epitope that discriminates between different cell types or different states of a common cell. An ideal marker is specific to a given cell type in normal conditions and/or during injury. Cell markers are very valuable tools for examining the function of cells in normal conditions as well as during disease. The discovery of various proteins specific to certain cells led to the production of cell-type-specific antibodies that have been used to identify cells.[1]

The techniques used for its detection can be immunohistochemistry, immunocytochemistry, methods that utilize transcriptional modulators and site-specific recombinases to label specific neuronal population,[2] in situ hybridization or fluorescence in situ hybridization (FISH).[3] A neuronal lineage marker can be a neuronal antigen that is recognized by an autoantibody for example Hu, which is highly restricted to neuronal nuclei. By immunohistochemistry, anti-Hu stains the nuclei of neurons.[4] To localize mRNA in brain tissue, one can use a fragment of DNA or RNA as a neuronal lineage marker, a hybridization probe that detects the presence of nucleotide sequences that are complementary to the sequence in the probe. This technique is known as in situ hybridization. Its application have been carried out in all different tissues, but particularly useful in neuroscience. Using this technique, it is possible to locate gene expression to specific cell types in specific regions and observe how changes in this distribution occur throughout the development and correlate with the behavioral manipulations.[5]