Recent events have demonstrated the public's pronounced lack of
knowledge regarding genetics and genetic engineering. While it is
unnecessary to possess a doctorate in order to understand the
intricacies of this rapidly-evolving science, it is important to have a
framework to consider the various challenges to societal norms and
biological changes to the population at large that genetics have
created.
To truly begin understanding a subject, context is always
necessary. To serve that end, here is a brief timeline outlining the
brief but paradigm shifting history of genetics:
1858: Charles
Darwin and Alfred Russel Wallace jointly announce the theory of natural
selection, which postulates that members of a population, whether plant
or animal, who better adapt to their natural environment not only
survive but pass on their traits to successive generations.
1859:
Charles Darwin publishes "On the Origin of Species by Means of Natural
Selection, or the Preservation of Favored Races in the Struggle for
Life". The work causes a stir in religious circles and society at large,
as it advances Darwin's theory of evolution to the masses.
1865:
Gregor Mendel's experimentation with peas leads to his discovery of
heredity and its transmission through discrete units. His research
demonstrated the idea that genes remain as distinct entities, even if
they create a blended-trait progeny. This ability to combine specific,
distinct traits into new organisms provides further support for Darwin's
theory of natural selection and evolution.
1869: Friedrich
Miescher isolates DNA itself from cells for the first time and calls the
mysterious substance "nuclein", while investigating pus in open wounds.
This substance would later be referred to as "nucleic acid" after
Miescher was able to separate the genetic material into a protein and
acid molecule.
1879: Walter Flemming discovers the cellular
process of mitosis, while observing chromosomes during animal cell
divisions. He would later collect his observations and detail the entire
process in 1882.
1900: Botanists Hugo de Vries, Carl Correns, and
Erich von Tschermak each rediscover Mendel's work while conducting
their own research regarding biological inheritance. The increased
understanding of cells and chromosomes, due to work from people like
Walter Flemming, allowed Mendel's concepts to finally have concrete
examples as illustrations.
1902: Walter Sutton observes that the
segregation of chromosomes during cellular meiosis matches the
inheritance patterns Mendel observed, thus demonstrating that
chromosomes play an integral role in passing on physical traits to
organisms.
1905: Nettie Stevens and Edmund Wilson independently
observe and describe the behavior of sex chromosomes, verifying that XX
determines a female animal while XY determines a male animal.
1909:
Wilhelm Johannsen creates the word "gene" to finally quantify Mendel's
distinctive trait units. He also devises the terms "genotype" and
"phenotype" in order to distinguish the differences between an
individual's inner, genetic traits and outward appearance
characteristics.
1911: Thomas Hunt Morgan study fruit fly
chromosomes and discover that chromosomes, in fact, are the structures
that carry genes. This work also leads to the formulation of genetic
linkage theory.
1927: Hermann J. Muller uses X-rays to induce
artificial gene mutations in fruit flies; after observing the results of
this accident, he formulates the principles of spontaneous gene
mutation in plants and animals.
1941: George Beadle and Edward
Tatum's experiments with irradiating red bread mold, leads to the
discovery that genes function by regulating specific chemical reactions.
They hypothesize that each specific gene is responsible for the
generation of an associated enzyme, which affects the organism's body
accordingly.
1944: Oswald Avery, Colin MacLeod, and Maclyn McCarty
demonstrate that DNA itself can adjust and change a cell's properties,
which in turn clarified the chemical governing abilities of genes that
Beadle and Tatum uncovered.
1951: Rosalind Franklin obtains the
first clear X-ray diffraction photographs of DNA itself; her work would
prove instrumental in solving DNA's structure despite being overlooked
publicly for decades.
1953: Building upon the photographic work of
Rosalind Franklin, Francis Crick and James Watson uncover and describe
the now-famous 'double helix' structure of DNA. Their efforts would lead
to receiving the Nobel Prize in 1962.
1955: Joe Hin Tijo is able
to determine that every human cell contains exactly 46 chromosomes,
broken apart into 23 distinctive pairs.
1966: Hamilton Smith and
Kent Wilcox discover and isolate the first known restriction enzyme,
HindII. These enzymes are able to cut DNA molecules down into segments
via specific sites. This knowledge would eventually lead to DNA sequence
analysis and genome mapping.
1972: Herb Boyer and Paul Berg
create the first recombinant DNA molecules, in which DNA from separate
species are combined together. The resultant hybrid molecule is then
inserted into a host cell. This would eventually lead to the production
of the first recombinant DNA medication, human insulin.
1975:
Frederick Sanger develops the Sanger method, which utilizes colored dyes
to identify the four specific nucleic acids that compose DNA. As a
result, DNA sequencing is born, allowing scientists to begin uncovering
the specific structures and functions of various genes.
1976:
Genentech, the first genetic engineering company, is founded by Herb
Boyer utilizing his recombinant DNA technology to produce human insulin
thereby launching biotech.
1988: The Human Genome Project is
formed, with its mission of determining the entire sequence of DNA that
all human chromosomes are composed of in every cell.
1989: Alec
Jeffreys coins the term "DNA fingerprinting" and was the first
researcher to apply DNA analysis technology towards paternity,
immigration, and murder cases.
1993: FlavrSavr tomatoes, the first
genetically-modified organisms ("GMO") available for public purchase
and consumption, come onto the market. They are engineered to have a
longer shelf life than naturally grown tomatoes.
1997: GeneTree,
the first company to use DNA testing to trace ancestry is launched. In
time, various other companies would enter the ancestry testing space.
2000:
The Human Genome Project unveils its initial results; 90% of the human
genome is fully sequenced and deemed to be 99.9% accurate after
additional testing and checking.
There are a myriad of other
events that have helped shape this scientific field, however by
examining this particular chain of history certain trends emerge. First,
the investigation into life's building blocks began well before the
hugely publicized discover of the double helix in 1953. Second, as with
most other movements, every major breakthrough stands upon the shoulders
of previous pioneers who may not have been able to see the entire
picture clearly but understood that the pieces they found were
important. This faith in progress and constant revisiting of the past
has led to breakthroughs in genetics that continue changing society on a
daily basis.
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