Gregor Mendel's classic experiments in plant genetics and heredity, published 35 years earler, are rediscovered and verified, sparking renewed interest in the field.

Walter S. Sutton reports after studying grasshopper sperm that each chromosome pairs with another physically similar one and that they separate during meiosis, one member of each pair goes to a different cell.

American pathologist develops tissue culture techniques.

Danish botanist Wilhelm Ludwig Johannsen coins the word "genes" for still misunderstood elements of heredity.

Thomas Hunt Morgan identifies XY male and XX female chromosomes and suggests that some traits and sex-linked. Later he shows how genes can mutate or change.

Invention of electron microscope enables researchers to see viruses. With better contrast and staining agents macromolecules like DNA eventually are exposed.

Invention of electrophoresis (use of an electric field to move charged particles dispersed in liquid) quickly becomes important in the development of immunology, biochemestry, and microbiology.

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