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The History of DNA

The following is a brief history of DNA discovery, analysis, and testing. Highlighted are the significant advances over the last 140 years that evolved into the DNA testing industry and the paternity testing information available today.

The theories of heredity attributed to Gregor Mendel, based on his genetic profiles of pea plants, are well known to any biology student. However, his genetic profiles were so unprecedented at the time, it took 34 years for the rest of the scientific community to catch up. The short monograph, Experiments with Plant Hybrids , in which Mendel described how traits were inherited, has become one of the most enduring and influential publications in the history of science.

The science of genetics was finally born when Mendel's work was rediscovered by three scientists - Hugo DeVries, Erich Von Tschermak, and Carl Correns - each one independently researching scientific literature for precedents to their own "original" work.

Andrei Nikolaevitch Belozersky isolated DNA in the pure state for the first time.

James Watson and Francis Crick proposed the double-stranded, helical, complementary, anti-parallel model for DNA. Nature magazine published James Watson's and Francis Crick's manuscript describing the double helical structure of DNA.

Coenberg discovered and isolated DNA polymerase, which became the first enzyme used to make DNA in a test tube.

The genetic code was "cracked". Marshall Nirenberg, Heinrich Mathaei, and Severo Ochoa demonstrated that a sequence of three nucleotide bases (a codon) determines each of 20 amino acids.

The first successful DNA cloning experiments were performed in California.

For the first time, scientists successfully transferred deoxyribonucleic acid (DNA) from one life form into another. Stanley Cohen and Annie Chang of Stanford University and Herbert Boyer of UCSF "spliced" sections of viral DNA and bacterial DNA with the same restriction enzyme, creating a plasmid with dual antibiotic resistance. They then spliced this recombinant DNA molecule into the DNA of a bacteria, thereby producing the first recombinant DNA organism.

The NIH released the first guidelines for recombinant DNA experimentation. The guidelines restricted many categories of experiments.

Studies by David Botstein and others found that when a restrictive enzyme is applied to DNA from different individuals, the resulting sets of fragments sometimes differ markedly from one person to the next. Such variations in DNA are called restriction fragment length polymorphisms (RFLPs), and they are extremely useful in genetic studies.

Kary Mullis and others at Cetus Corporation in Berkeley, California, invented a technique for multiplying DNA sequences in vitro by, the polymerase chain reaction (PCR). PCR has been called the most revolutionary new technique in molecular biology in the 1980s. Cetus patented the process, and in the summer of 1991 sold the patent to Hoffman-La Roche, Inc. for $300 million.

Alec Jeffreys introduces technique for DNA fingerprinting to identify individuals.

Genetic fingerprinting enters the court room.

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.

The Human Genome Project, the international effort to map all of the genes in the human body, was launched. Estimated cost: $13 billion.

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.

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.

Former football player O.J. Simpson is found not guilty in a high-profile double-murder trial in which PCR and DNA fingerprinting play prominent roles.

Researchers at Scotland's Roslin Institute report that they have cloned a sheep--named Dolly--from the cell of an adult ewe. Polly, the first sheep cloned by nuclear transfer technology bearing a human gene, appears later. Also, leading geneticists expressed shock and dismay as word spread of the US Patent and Trademark Office announcement that it would allow patents on expressed sequence tags (ESTs), short sequences of human DNA that have proven useful in genome mapping.

A rough draft of the human genome map is produced, showing the locations of more than 30,000 genes.

Scientists announce that they have essentially cracked the human genetic code - a decade-long effort by over 1,000 researchers that could revolutionize the diagnosis and treatment of diseases once considered incurable. Decoding the 3 billion chemical "letters" in human DNA is seen as one of history's great scientific milestones - the biological equivalent of the moon landing.