Wilhelm Ludvig Johannsen

Wilhelm Ludvig Johannsen

Danish biologist, professor
Date of Birth: 03.02.1857
Country: Denmark

  1. Biography of Wilhelm Johannsen
  2. Contributions
  3. Legacy

Biography of Wilhelm Johannsen

Wilhelm Johannsen was a Danish biologist, professor at the Institute of Plant Physiology at the University of Copenhagen, and a member of the Swedish Academy of Sciences. He conducted experiments on barley and beans to demonstrate the inefficiency of selection in self-pollinating plants. Based on these experiments, he formulated the "law of pure lines" and disproved Francis Galton's laws of partial inheritance of acquired traits in 1889 and 1897.


In 1903, Johannsen introduced the term "population" in his work "On Heredity in Populations and Pure Lines." This concept was crucial in understanding the genetic variation within a group of organisms. Additionally, in 1909, Johannsen introduced the terms "gene," "genotype," and "phenotype" in his work "Elements of the Exact Theory of Heredity." These terms became fundamental in the field of genetics and laid the foundation for modern genetic studies.


Wilhelm Johannsen's research and contributions in the field of genetics revolutionized the understanding of inheritance and genetic variation. His work on pure lines and populations paved the way for advancements in genetics, laying the groundwork for future studies in heredity. His introduction of key terms such as "gene" and "genotype" continues to shape our understanding of genetics to this day. Johannsen's work remains influential and his ideas have had a lasting impact on the field of biology.