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Darwin published “On the Origin of Species”, proposing continual evolution of species
Darwin’s understanding of genetics and hereditary concepts appear in his writing, introducing the term “survival of the fittest.” -
Mendel’s Peas
George Mendel describes his experiments with peas, showing that heredity is transmitted in discrete units -
DNA First Isolated
Friedrich Miescher isolates DNA for the first time when working with white blood cells. -
Mitosis Observed
Walter Flemming describes chromosome behavior during animal cell division. -
Rediscovery of Mendel’s Work
DeVries, Correns, and Tschermak rediscover and bring awareness to the Mendelian laws of inheritance -
Chromosome Theory of Heredity
Walter Sutton, a graduate student in E. B. Wilson's lab at Columbia University, observed that in the process of cell division, called meiosis, that produces sperm and egg cells, each sperm or egg receives only one chromosome of each type. -
Orderly Inheritance of Disease Observed
Archibald Garrod observes that the disease alkaptonuria is inherited according to Mendelian rules. -
The Word Gene is Coined
Danish botanist Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity.He also made the distinction between the outward appearance of an individual (phenotype) and its genetic traits (genotype). -
Fruit Flies Illuminate the Chromosome Theory
Using fruit flies as a model organism, Thomas Hunt Morgan and his group at Columbia University showed that genes, strung on chromosomes, are the units of heredity. -
One Gene, One Enzyme
George Beadle and Edward Tatum, through experiments on the red bread mold Neurospora crassa, showed that genes act by regulating distinct chemical events - affirming the "one gene, one enzyme" hypothesis -
X-ray Diffraction of DNA
William Astbury, a British scientist, obtained the first X-ray diffraction pattern of DNA. -
DNA is “Transforming Principle”
Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA (not proteins) can transform the properties of cells, clarifying the chemical nature of genes. -
Jumping Genes
Barbara McClintock discovers that genes can jump around on chromosomes, showing that the genome is more dynamic than previously thought. -
Genes are Made of DNA
Alfred Hershey and Martha Chase showed that only the DNA of a virus needs to enter a bacterium to infect it. -
DNA Double Helix
Francis Crick and James Watson described the double helix structure of DNA based on images taken by Rosalind Franklin -
46 Human Chromosomes
Joe Hin Tjio defined 46 as the exact number of human chromosomes. -
DNA Copying Enzyme
Arthur Kornberg and his colleagues isolated DNA polymerase, an enzyme later used for all kinds of recombinant DNA techniques and for sequencing. -
Cause of Disease Traced to Alteration
Sickle cell anemia was first described in 1910, after Ernest E. Irons, an intern at Chicago's Presbyterian Hospital, noticed elongated cells in a blood smear from Walter C. Noel, a dental student with severe anemia. -
Semiconservative Replication of DNA
Matthew Meselson and Franklin Stahl demonstrated that DNA replicates semiconservatively, with each strand in a DNA molecule from the parent generation pairing with a new strand in the daughter generation -
Chromosome Abnormalities Identified
Professor Jerome Lejeune and his colleagues discovered that Down syndrome, first classified by J. L. H. Down in 1866, is caused by trisomy 21 - that is, having three instead of 2 copies of chromosome 21. -
mRNA Ferries Information
Sydney Brenner, Francois Jacob, and Matthew Meselson discovered that mRNA is the molecule that takes information from DNA in the nucleus to the protein-making machinery in the cytoplasm. -
First Screen for Metabolic Defect in Newborns
Robert Guthrie, a doctor and bacterial scientist at the University of Buffalo Children's Hospital, developed a way to test whether newborn babies have phenylketonuria (PKU), an inability to digest the amino acid phenylalanine. -
Genetic Code Cracked
Over the course of several years, Marshall Nirenberg, Har Khorana and Severo Ochoa and their colleagues elucidated the genetic code - showing how nucleic acids with their 4-letter alphabet determine the order of the 20 kinds of amino acids in proteins. -
First Restriction Enzymes Described
Several groups of researchers - including M. Meselson's group at Harvard and H. O. Smith, K. W. Wilcox, and T. J. Kelley at Johns Hopkins - studied and characterized the first restriction nucleases, enzymes that revolutionized molecular biologists' ability to manipulate DNA. -
First Recombinant DNA
The first production of recombinant DNA molecules, using restriction enzymes, occurred in the early 1970s. -
First Animal Gene Cloned
Stanford and UCSF researchers fused a segment of DNA containing a gene from the African clawed frog Xenopus with DNA from the bacterium E. coli and placed the resulting DNA back into an E. coli cell. -
First Genetic Engineering Company
The first genetic engineering company, Genentech, was founded in 1976. -
DNA Sequencing
Sanger and his colleagues, and Maxam and Gilbert developed rapid DNA sequencing methods. -
Introns Discovered
Richard Roberts' and Phil Sharp's labs showed that eukaryotic genes contain many interruptions, called introns. -
First Transgenic Mice and Fruit Flies
Scientists had been able to add new genes to bacterial cells for several years. In the early 1980s, they figured out how to add stably-inherited new genes to animals. -
GenBank Database Formed
GenBank, NIH's publicly accessible genetic sequence database, was formed at Los Alamos National Laboratory. -
First Disease Gene Mapped
A genetic marker linked to Huntington disease was found on chromosome 4 in 1983, making Huntington disease, or HD, the first genetic disease mapped using DNA polymorphisms. -
PCR Invented
PCR - the polymerase chain reaction - is a technique for amplifying DNA that dramatically boosted the pace of genetic research. -
First Time Gene Positionally Cloned
Positional cloning is the method of finding a gene without any knowledge of the protein it encodes. The first human disease gene identified by positional cloning was one for chronic granulomatous disease. -
First Human Genetic Map
The first comprehensive genetic map of human chromosomes was based on 400 restriction fragment length polymorphisms (RFLPs), which are variations in DNA sequence that can be observed by digesting DNA with restriction enzymes. -
YACs Developed
Yeast artificial chromosomes (YAC) can carry large segments of DNA from other species, like humans. -
Microsatellites, New Genetic Markers
A microsatellite is a stretch of DNA made of a two to four base-pair long sequence that is repeated in tandem - e.g. a stretch of DNA that looks like this: CAGCAGCAGCAGCAGCAGCAG. -
Sequence-tagged Sights, Another Marker
A sequence-tagged site (STS) is a unique stretch of DNA that polymerase chain reaction (PCR) can easily detect. -
Launch of the Human Genome Project
The Human Genome Project officialy began in 1990. Beginning in December 1984, the U.S. Department of Energy (DOE), National Institutes of Health (NIH) and international groups had sponsored meetings to consider the feasibility and usefulness of mapping and sequencing the human genome. -
ELSI Founded
Ethical, Legal and Social Implications (ELSI) programs founded at NIH and DOE. -
Research on BACs
In 1990, researchers began to study how to efficiently produce stable carriers of large DNA inserts in bacteria, so-called BACs. -
ESTs, Fragments of Genes
An expressed-sequence tag (EST) is a stretch of DNA sequence made by copying a portion of an mRNA molecule. -
Second-generation Genetic Map of Human Genome
A team from France built a low-resolution, microsatellite genetic map of the entire human genome. -
Data Release Guidelines Established
The DOE and NIH set up an agreement on how to share resources and release data to the community of researchers. -
New HGP Five-year Plan
Unexpectedly rapid progress toward the goals established in 1990 led the National Institutes of Health and the Department of Energy to establish a new set of goals for the Human Genome Project in 1993, two years ahead of schedule. -
FLAVR SAVR Tomato
The FDA approved the sale of the first genetically modified food - the FLAVR SAVR tomato, deeming it as safe as conventionally-bred tomatoes. -
Detailed Human Genetic Map
One of the primary goals of the Human Genome Project's 1993 five-year plan was to complete a detailed genetic map of the human genome by 1995. Genetic mapping was a critical early step in the hunt for disease genes - allowing researchers to find on which chromosome a gene lies and approximately where in that chromosome. Researchers completed the genetic mapping goal one year ahead of schedule, and the map was denser (had more markers) than originally proposed. -
Microbial Genome Project
The DOE began a Microbial Genome Program in late 1994 to sequence the genomes of some bacteria. -
Ban on Genetic Discrimination in Workplace
The U.S. Equal Employment Opportunity Commission extended workplace protections under the Americans with Disabilities Act to cover discrimination based on genetic information. -
Physical Mal of Human Genome Completed
A physical map uses sequence-tagged sites (STSs) as markers to order large segments of DNA. The map built by 1995 was a significant milestone toward that goal; it contained 15,086 STSs, spaced an average of 199,000 base pairs apart. -
International Strategy Meeting on Human Genome Sequencing
The first international strategy meeting on human genome sequencing drew scientists from the countries in Europe, North America, and Asia funding human genome sequencing projects. -
Human Gene Map Created
Scientists created a map showing the locations of ESTs (expressed sequence tags) representing fragments of more than 16,000 genes from throughout the genome. -
Human DNA Sequence Begins
In 1996, the National Human Genome Research Institute funded pilot projects to find efficient strategies for completely sequencing the human genome. -
Recommendations on Genetic Testing
A Task Force on Genetic Testing was created by the NIH-DOE Working Group on Ethical, Legal, and Social Implications of Human Genome Research to review genetic testing in the United States and make recommendations to ensure the development of safe and effective genetic tests -
HGP Map Included 30,000 Human Genes
In October 1998, HGP researchers released a gene map that included 30,000 human genes, estimated to represent approximately one-third of the total human genes. -
Genome of Roundworm C. elegans Sequenced
In December 1998, the first genome sequence of a multicellular organism, the roundworm Caenorhabditis elegans, was completed. -
Full-Scale Human Genome Sequencing
In March 1999, HGP participants advanced their goal of obtaining draft sequence covering 90 percent of the human genome to 2000, a year and a half before projected previously. -
Chromosome 22
In December 1999, the HGP completed the first finished, full-length sequence of a human chromosome - chromosome 22. This accomplishment demonstrated the power of the HGP method of clone-by-clone sequencing to obtain large amounts of highly accurate sequence. -
Free Access to Genomic Information
In March 2000, U.S. President Clinton and U.K. Prime Minister Tony Blair stated that raw, fundamental data about human genome sequence and its variations should be freely available. -
First Draft of the Human Genome Sequence Released
The Human Genome Project international consortium published a first draft and initial analysis of the human genome sequence. The draft sequence covered more than 90 percent of the human genome. -
Researchers Find Genetic Variation Associated with Prostate Cancer
Researchers identified a gene on chromosome 1 associated with a hereditary form of prostate cancer. -
Human Genome Project Completed
The International Human Genome Sequencing Consortium announced the successful completion of the Human Genome Project more than two years ahead of schedule and under budget. -
Fiftieth Anniversary of Watson and Crick’s Description of the Double Helix
In April 1953, a paper appeared in the journal Nature that proposed a double helix structure for deoxyribose nucleic acid DNA. -
The First National DNA Day Celebrated
The United States Congress passed a resolution setting aside April 25th as National DNA Day.