| 1856 | Gregor Mendel begins experiments cross-breeding the garden pea (Pisum sativum). |
| 1859 | Charles Darwin publishes On the Origin of Species. |
| 1865 | Mendel presents his paper on the results and his interpretation of his experiments, at the monthly meetings, 8 February and 8 March, of the Naturforschender Verein (Natural Science Society) in Brno. |
| 1866 | Mendel publishes Versuche über Pflanzen-hybriden in the Society's journal. He sends out offprints but these are ignored. |
| 1871 | Friedrich Miescher reports the discovery of nuclein from isolated cell nuclei; this is the first work with nucleic acids. |
| 1887 | August Weisman, under the microscope, disentangles the dance of the chromosomes in meiosis. He points out that each chromosome must carry a great number of determinants of hereditary characters, and speculates about the minute size of them. |
| 1900 | Carl Correns and Hugo de Vries, working independently, rediscover Mendel's rules and then his paper; Erich von Tschermak plays a minor role. William Bateson publicises Mendel's work to the Royal Horticultural Society of London and soon translates his paper. |
| 1902 | Walter Sutton promotes the chromosome theory of inheritance that chromosomes can be seen to behave just like the Mendelian elements (soon to be called genes) and that each chromosome must carry many of them; Theodor Boveri makes a similar observation. |
| 1902 - 1909 | Bateson coins the terms genetics, allelomorph (now shortened to allele), homozygote, heterozygote and others. |
| 1909 | Archibald Garrod originates the subspecialty of biochemical genetics by demonstrating that certain human diseases are inborn errors of metabolism, inherited as Mendelian recessive characters. |
| 1910 | Thomas Hunt Morgan finds a mutant eye-colour in the fruitfly Drosophila and discovers sex linkage. He proposes that the genes located on the same chromosome are linked together and can recombine by exchange of chromosome segments, called crossing over. |
| 1913 | Alfred Henry Sturtevant draws the first genetic map, using cross-over frequencies between six sex-linked Drosophila genes to show their relative locations on the X chromosome. |
| 1927 | Hermann Muller demonstrates that X-rays can induce genetic mutations in Drosophila. |
| 1931 | Harriet Creighton and Barbara McClintock, and Curt Stern independently, find the first direct proof, in cells under the microscope, that crossing-over takes place. |
| 1941 | George Beadle and Edward Tatum, working with the biochemical genetics of the mold Neurospora, propose the "one gene-one enzyme" theory. |
| 1940s | Max Delbrück and Salvador Luria, and Jacques Monod independently, demonstrate that bacteria have genes. |
| 1944 | Oswald Avery, Colin MacLeod, and Maclyn McCarty publish strong evidence that DNA is the hereditary material. |
| 1949 | Frederick Sanger, working with the insulin molecule, publishes the first evidence that the sequence of amino acids in a protein chain is unique to that protein. |
| 1949 | Erwin Chargaff publishes evidence that the proportions of the four kinds of nucleotides, the components that make up a strand of DNA, are the same in all cells of a given creature but vary greatly from one species to another. DNA is set free to carry genetic information. |
| 1953 | James Watson and Francis Crick elucidate the three-dimensional molecular structure of DNA, the double helix. They relied partly on unpublished X-ray crystallographic data obtained by Rosalind Franklin and by Maurice Wilkins. |
| 1957 - 1958 | Crick proposes the Central Dogma of molecular biology, which states that genetic information, meaning specific sequences, can move among nucleic acids and into protein, "but that once information has passed into protein it cannot get out again". |
| 1958 | Matthew Meselson and Franklin Stahl demonstrate that DNA replicates semi-conservatively, as the Watson-Crick structure requires. |
| 1950s | François Jacob and Jacques Monod, in a long series of experiments, establish the existence of control functions located on the chromosome which turn the expression of genes on or off. |
| 1961 | Jacob, Crick, Sydney Brenner and others work out the general scheme of the transcription of the information in DNA into messenger RNA and the translation of mRNA into protein. Brenner, Jacob, and Meselson find mRNA in bacterial cells. |
| 1961 | Crick and colleagues demonstrate that the genetic information is carried in three-nucleotide sets, called codons, of which there are 64, each coding for one of the 20 amino acids of protein chains; three codons turn out to be stop signals. |
| 1961 | Marshall Nirenberg and Heinrich Matthaei get the first and second codons to be identified. |
| 1961 - 1967 | Nirenberg, Severo Ochoa, H. Gobind Khorana and others, in a furious race, determine the rest of the genetic code. |
| 1970s | Paul Berg, Stanley N. Cohen and others develop methods for cutting DNA up and recombining the fragments in novel sequences: recombinant DNA, or genetic engineering, is launched. |
| 1977 | Sanger invents a remarkable method for sequencing DNA; Walter Gilbert and Allan Maxam independently devise another. |
| 1983 | For the first time, the gene defect that causes a human disorder (Huntington's disease) is located exactly on a chromosome and so isolated for study. |
| 1995 | First bacterial genome sequenced (Haemophilus influenzae). |
| 1995 | Genomes sequenced of bacteria Mycoplasma genitalium and Escherichia coli, yeast. |
| 2000 | (Saccharomyces cerevisiae), roundworm (Caenorhabditis elegans), fruitfly (Drosophila melanogaster) and mustard cress (Arabidopsis thaliana). |
| 1999 | First human chromosome sequenced (chromosome 22). |
| 2002 | The mouse genome sequenced. |
| 2003 | First full draft of the human-genome sequence completed. |
Abbey of St Thomas, Brno, Czech Republic: Mendel Museum of Genetics, http://www.mendel-museum.org/eng/1online/ (accessed 23 April 2004).