DISORDERS, such as DOWN SYNDROME. Though as yet
there are few treatments to alter the course of
genetic and chromosomal disorders, continuing
research holds promise that doctors may in the
foreseeable future have the ability to offer effec-
tive therapeutic interventions.
Traditions in Medical HistoryIn the 1660s English scientist Robert Hooke
(1635–1703) used his newest invention, the com-
pound light microscope, to examine a thin slice of
cork. The increased magnifying power of this new
microscope’s dual lenses was considerable com-
pared to the standard single-lens microscope of the
time; and with its improved light source of reflected
and focused candlelight, it revealed a level of struc-
ture in living organisms scientists had not known
existed: the tight clustering of tiny compartments.
Hooke called these compartments cells because
they reminded him of the living quarters of monks
in monasteries. Hooke described his findings and
explorations of cells in his 1665 manuscript
Micrografia,which became an epochal publication
in the field of biology during Hooke’s lifetime—
short order for such significant recognition.
Not for another 150 years, however, did biolo-
gists finally and fully comprehend the interrela-
tionships and organizations of cells within
organisms. British botanist Robert Brown
(1773–1858) discovered the cell nucleus in 1831,
establishing it as the foundation of cell division; 36
years later Swiss biologist and chemist (Johann)
Friedrich Miescher (1844–1895) isolated and iden-
tified the active protein–acid structure in the cell
nucleus responsible for cell division. Miescher
called the structure nuclein, and speculated that it
not only was the key player in cell reproduction
but also was the decanter of heredity itself.
Miescher would never know the prophecy of his
speculation because the technology to further
explore such a hypothesis was still three quarters
of a century away.
The words might well have gone from the sci-
entist’s mouth to the monk’s ear, however. Merely
a country’s border away Gregor Johann Mendel
(1822–1884) spent his days nurturing sweet peas
in his monastery’s gardens. Mendel, an Augustin-
ian monk, observed in nature what Miescher
studied in the laboratory: the paths of heredity.
Mendel crossbred his sweet peas, detailing the pat-
terns of their varieties and alternate characteris-
tics. Mendel would later achieve full recognition
for identifying the predictable variations that
occurred as the consequence of what he called
paired elements of heredity. Less than two years
apart these two researchers, the chemist and the
botanist, published their respective findings.
In 1933 Thomas Hunt Morgan (1866–1945)
received the Nobel Prize in Physiology or Medi-
cine for proving the existence of chromosomes. By
the 1940s numerous scientists were trying to
unravel the cryptogram of the chromosome.
James Watson and Francis Crick, working in col-
laboration, and Maurice Wilkins, working inde-
pendently, finally succeeded. In 1953 Watson and
Crick unveiled their model of the double-helix
structure of deoxyribonucleic acid. DNA, the mas-
ter code of genetics, was no longer a secret. Wat-
son, Crick, and Wilkins received the 1962 Nobel
Prize in Physiology or Medicine “For their discov-
eries concerning the molecular structure of
nucleic acids and its significance for information
transfer in living material.”
Increasingly sophisticated technology made it
possible to study the activity of the cell at the level
of the molecule. Following numerous affirming
discoveries about genes and DNA sequencing in the
1960s, 1970s, and 1980s, scientists began to talk of
sequencing the human genome—unraveling the
molecule of heredity. The effort began formally in
1988 with James Watson at the helm of the plan-
ning process. Watson saw the Human Genome
Project through its official launch in 1990. Only 13
years later, 2 years ahead of schedule and on the
50th anniversary of Watson and Crick’s unveiling
of the double helix, the Human Genome Project
announced completion of the sequencing of the
human genome. “Never would I have dreamed in
1953 that my scientific life would encompass the
path from DNA’s double helix to the three billion
steps of the human genome,” Watson said in com-
ments to the media at the events celebrating the
completion of the Human Genome Project.Breakthrough Research and Treatment Advances
The high-tech world of genetics and molecular
medicine continues to drive the direction of medi-
cine. RECOMBINANT DNAtechnology debuted in theGenetics and Molecular Medicine 111