Agonist: An agent that mimics the actions or effects of another agent at a receptor (e.g., a drug that mimics the effects of a neurotransmitter).
Allele: One of two or more forms of a gene that reside at the same position on a pair of chromosomes; different alleles of a gene may serve the same function (e.g., code for an enzyme that breaks down alcohol) but may result in proteins with different...