Molecular marker

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Molecular marker is a term with a number of uses. It is any kind of molecule indicating the existence of a chemical or physical process. In particular, in the fields of geology and astrobiology, biomarkers (also known as biosignatures) are sometimes understood as molecules indicating the presence (past or present) of living organisms. It can also be a molecule used as fiscal marker to distinguish lower-taxed items from higher-taxed ones when they otherwise can be substituted (see fuel dyes).

In medicine, a molecular marker can be a substance that is introduced in an organism as a means to examine something. For example, rubidium chloride is used as a radioactive isotope to evaluate perfusion of heart muscle. In biology and medicine, a molecular marker (biomarker) can be a substance native to the organism whose detection indicates a particular disease state (for example, the presence of an antibody may indicate an infection). In genetics, a molecular marker (identified as genetic marker) is a fragment of DNA sequence that is associated to a part of the genome.

Molecular markers are used in molecular biology and biotechnology experiments where they use to identify a particular sequence of DNA. As the DNA sequences are very highly specific, they can be identified with the help of the known molecular markers which can find out a particular sequence of DNA from a group of unknown.