1. A molecule (which may be a small polymer) that initiates the synthesis of a larger structure. SYN: starter. 2. A pheromone that causes a long-term physiologic change.
* * *
prim·er 'prī-mər n a molecule (as a short strand of RNA or DNA) whose presence is required for formation of another molecule (as a longer chain of DNA)
* * *
prim·er (prīmґər) 1. a substance that prepares for or facilitates the action of another. 2. in genetics, a short piece of DNA or RNA complementary to a given nucleic acid sequence; it acts as the nucleation point from which nucleotides are added to the growing chain, as in DNA replication, sequencing, or the polymerase chain reaction.Medical dictionary. 2011.