From Mendel to Monica
BY MICHAEL D. LEMONICK AND DICK THOMPSON 1866 Austrian botanist and monk Gregor Mendel proposes basic laws of heredity based on cross-breeding experiments with pea plants. His findings, published in a local natural-history journal, are largely ignored for more than 30 years.
1882 While examining salamander larvae under a microscope, German embryologist Walther Fleming spots tiny threads within the cells' nuclei that appear to be dividing. The threads will later turn out to be chromosomes.
1883 Francis Galton, a cousin of Charles Darwin's and an advocate of improving the human race by means of selective breeding, coins the word eugenics.
1910 U.S. biologist Thomas Hunt Morgan's experiments with fruit flies reveal that some genetically determined traits are sex linked. His work also confirms that the genes determining these traits reside on chromosomes.
1926 U.S. biologist Hermann Muller discovers that X rays can cause genetic mutations in fruit flies.
1932 Publication of Aldous Huxley's novel Brave New World, which presents a dystopian view of genetic engineering.
1944 Working with pneumococcus bacteria, Oswald Avery, Colin MacLeod and Maclyn McCarty prove that DNA, not protein, is the hereditary material in most living organisms.
1950 British physician Douglas Bevis describes how amniocentesis can be used to test fetuses for Rh-factor incompatibility. The prenatal test will later be used to screen for a battery of genetic disorders.
1953 American biochemist James Watson and British biophysicist Francis Crick announce their discovery of the double-helix structure of DNA, the molecule that carries the genetic code.
1964 Stanford geneticist Charles Yanofsky and colleagues prove that the sequence of nucleotides in DNA corresponds exactly to the sequence of amino acids in proteins.
1969 A Harvard Medical School team isolates the first gene: a snippet of bacterial DNA that plays a role in the metabolism of sugar.
1970 University of Wisconsin researchers synthesize a gene from scratch.
1973 American biochemists Stanley Cohen and Herbert Boyer insert a gene from an African clawed toad into bacterial DNA, where it begins to work. Their experiment marks the beginning of genetic engineering.
1975 Scientists at an international meeting in Asilomar, Calif., call for guidelines for recombinant-DNA research.
1976 The first genetic-engineering company, Genentech, is founded in South San Francisco.
1978 Scientists from Genentech and a Duarte, Calif., medical center clone the gene for human insulin.
1980 Researchers successfully introduce a human gene--one that codes for the protein interferon--into a bacterium.
1980 Martin Cline and co-workers create a transgenic mouse, transferring functional genes from one animal into another.
1982 The U.S. Food and Drug Administration approves the first genetically engineered drug, a form of human insulin produced by bacteria.
1983 Researchers locate a genetic marker for Huntington's disease on chromosome 4. Their achievement leads to a screening test, but the disorder remains incurable. The gene itself will be found 10 years later.
1983 While driving along a California highway, Kary Mullis, a biochemist at Cetus Corp., conceives of the so-called polymerase chain reaction, or PCR, a technique that will enable scientists to rapidly reproduce tiny snippets of DNA.
1984 Alec Jeffreys, of Britain's University of Leicester, develops "genetic fingerprinting," which uses unique sequences of DNA to identify individuals.
1985 First use of genetic fingerprinting in a criminal investigation.
1986 The FDA approves the first genetically engineered vaccine for humans, for hepatitis B.
1988 Harvard University is awarded the first patent for a genetically altered animal, a mouse that is highly susceptible to breast cancer.
1989 Creation of the National Center for Human Genome Research, headed by James Watson, which will oversee the $3 billion U.S. effort to map and sequence all human DNA by 2005.
1990 Formal launch of the international Human Genome Project.
1990 American geneticist W. French Anderson performs the first gene therapy on a four-year-old girl with an immune-system disorder called ADA deficiency.
1990 Publication of Michael Crichton's novel Jurassic Park, in which bioengineered dinosaurs roam a paleontological theme park; the experiment goes awry, with deadly results.
1991 Analyzing chromosomes from women in cancer-prone families, Mary-Claire King, of the University of California, Berkeley, finds evidence that a gene on chromosome 17 causes the inherited form of breast cancer and also increases the risk of ovarian cancer.
1992 The U.S. Army begins collecting blood and tissue samples from all new recruits as part of a "genetic dog tag" program aimed at better identification of soldiers killed in combat.
1992 American and British scientists unveil a technique for testing embryos in vitro for genetic abnormalities such as cystic fibrosis and hemophilia.
1993 After analyzing the family trees of gay men and the DNA of pairs of homosexual brothers, biochemists at the U.S. National Cancer Institute report that at least one gene related to homosexuality resides on the X chromosome, which is inherited from the mother.
1993 George Washington University researchers clone human embryos and nurture them in a Petri dish for several days. The project provokes protests from ethicists, politicians and critics of genetic engineering.
1993 An international research team, led by Daniel Cohen, of the Center for the Study of Human Polymorphisms in Paris, produces a rough map of all 23 pairs of human chromosomes.
1995 Researchers at Duke University Medical Center report that they have transplanted hearts from genetically altered pigs into baboons. All three transgenic hearts survived at least a few hours, proving that cross-species operations are possible.
1995 Former football player O.J. Simpson is found not guilty in a high-profile double-murder trial in which PCR and DNA fingerprinting play a prominent but apparently unpersuasive role.
1997 Researchers at Scotland's Roslin Institute, led by embryologist Ian Wilmut, report that they have cloned a sheep--named Dolly--from the cell of an adult ewe.
1998 Biologist Craig Venter announces ambitious plans to decode the entire human genome by 2001.
1998 University of Hawaii scientists, using a variation of Wilmut's technique, clone a mouse, creating not only dozens of copies but three generations of cloned clones.
1998 DNA analyses of semen stains on a dress worn by Monica Lewinsky match DNA from a blood sample taken from President Clinton.
1998 DNA testing proves that U.S. President Thomas Jefferson had at least one child with one of his slaves, Sally Hemings.
1998 Two research teams succeed in growing embryonic stem cells.
1998 Scientists at Japan's Kinki University clone eight identical calves using cells taken from a single adult cow.
2003 The Human Genome Project's current target date for sequencing all human DNA.
--WITH REPORTING BY DAN CRAY/LOS ANGELES, ANDREA DORFMAN/NEW YORK AND KATE NOBLE/CAMBRIDGE. © 1999 TIME Magazine
Última Atualização: 23/Set/99
