Which geneticist coined the term “gene” in 1909?

Wilhelm Johannsen coined the term “gene” in 1909. He introduced the word to describe the hereditary units underlying biological traits, replacing less precise language used in early genetics.

Johannsen was a Danish botanist who studied inheritance in beans. He also introduced the terms genotype and phenotype, helping distinguish an organism’s inherited genetic constitution from its observable characteristics.

The concept of a gene changed considerably after Johannsen’s work. Early geneticists treated genes as abstract units, while twentieth-century research connected them to chromosomes, DNA sequences, and the production of functional RNA or proteins. Modern genetics also recognizes that gene activity can be regulated and that some genes produce noncoding RNAs.

Gregor Mendel had discovered key inheritance patterns decades earlier, but he did not use the word gene. Thomas Hunt Morgan later supplied strong evidence linking genes to chromosomes through experiments with fruit flies.