After the rediscovery of Mendel’s work in 1900, Bateson introduced many of the terms in current usage: genetic, zygote, homozygote, heterozygote, allelomorph (later shortened to allele), and F1 and F2 generations. Mendel’s term ‘Merkmal’ was translated as either character, unit character, or factor (Bateson’s choice). Johannsen proposed using the word gene in 1909.