a unit of inheritance that is carried on a chromosome, controls transmission of hereditary characters, and consists of DNA or, in some viruses, RNA
Gregor Mendel (1822–84) discovered that inheritance comes in discrete particles, each from one parent or the other, rather than as substances blended from both parents. His idea was rediscovered in 1900, and the word gene coined thereafter. But genes not only assort independently as strings of particles. DNA itself is made up of strings of digits – particles again — Professor Richard Dawkins
[German Gen, short for Pangen, from Greek pan- all + -gen, from genos race]