A Historical Timeline: Cracking the Code of Life

1859-1902 | 1910-1962 | 1966-1978 | 1980-1988 | 1990-2003 | Next>>

1859
Charles Darwin publishes On The Origin of Species by Means of Natural Selection or The Preservation of Favoured Races in the Struggle for Life. Although Darwin's landmark theory did not specify the means by which characteristics are inherited (because the mechanism of heredity had not been determined), his key premise was that evolution occurs through the selection of inherent and transmissible, rather than acquired, characteristics between individual members of a species.

1843-1868
Gregor Mendel, an Austrian monk now celebrated as "the father of genetics," conducts his experiments breeding the garden pea. Mendel established two laws that anticipated modern genetic research. The law of segregation states that the "factors" (what we now call genes) that determine such traits as height and eye color come in pairs, and the pairs separate when sperm and egg cells reproduce in the process called meiosis. As a result, each offspring gets one form, or allele, of the pair from each parent, which explains why children exhibit traits of both their parents. Mendel's law of independent assortment states that the pairs of alleles separate independently of each other during meiosis. "My scientific labors have brought me a great deal of satisfaction," Mendel wrote, "and I am convinced that before long the entire world will praise the result of these labors." Mendel's work, however, was largely ignored for 30 years.

1869
Swiss physician Frederick Miescher isolates DNA from human white blood cells and the sperm of trout; he calls the substance "nuclein."

1879
Walther Fleming, a German biologist, uses brightly colored dyes to help him observe long, thin threads in the nuclei of cells that appear to be dividing. These threads are later called chromosomes. In 1882, Fleming publishes a summary of the process, which he calls "mitosis."

1883
Francis Galton of England, a cousin of Charles Darwin's, coins the word and helps popularize the notion of eugenics. Eugenics, the theory of improving human "stock" through "selective breeding," ultimately leads to Nazi racial cleansing and forced sterilization laws in the United States, as well as modern prenatal testing and genetic counseling.

1900
Three European scientists, Hugo de Vries, Karl Correns, and Erich von Tschermak independently publish papers that confirm Mendel's Laws of Inheritance, giving Mendel's work its long-delayed recognition.

1902
Two cytologists, the American Walter Sutton and the German Theodor Boveri, reveal that genes are found on chromosomes, and that chromosomes come in pairs that are similar to each other.

1859-1902 | 1910-1962 | 1966-1978 | 1980-1988 | 1990-2003 | Next>>