What is a gene?

A. the different forms of a trait

B. a segment of DNA that is the basic unit of heredity

C. the appearance or characteristics that are seen in an organism

D. an organism's allele combination

(in informal use) a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring. (in technical use) a distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule which a cell (or virus) may synthesize.