FUNDAMENTAL BUILDING BLOCKS 283
half of the double helix; then,
carrying its genetic information
as the sequence of bases, it would
leave the cell nucleus to become
involved in the protein production.
Second, when the whole length
of the double helix was unzipped,
each part would act as a template
to build a new complementary
partner—resulting in two lengths
of DNA that were identical to the
original and to each other. In this
way, DNA was copied as cells
divided into two for growth and
repair throughout an organism’s
life—and as sperm and eggs, the
sex cells, carried their quotient of
the genes to make a fertilized egg,
so beginning the next generation.
“Secret of life”
On February 28, 1953, elated by
their discovery, Watson and Crick
went for lunch to The Eagle, one of
Cambridge’s oldest inns, where
colleagues from the Cavendish and
other laboratories often met. Crick
is said to have startled drinkers by
announcing that he and Watson
had discovered “the secret of life”—
or so Watson later recalled in his
book, The Double Helix, though
Crick denied this really happened.
In 1962, Watson, Crick, and
Wilkins were awarded the Nobel
Prize in Physiology or Medicine
“for their discoveries concerning
the molecular structure of nucleic
acids and its significance for
information transfer in living
material.” The award, however,
was surrounded in controversy.
In the preceding years, Rosalind
Franklin had received little official
credit for producing the key X-ray
images and for writing the reports
that helped to direct Watson
and Crick’s research. She died of
ovarian cancer in 1958, at only 37,
and was therefore ineligible
for the Nobel Prize in 1962, since
the prizes are not awarded
posthumously. Some said the
award should have been made
earlier, with Franklin as one of
the co-recipients, but the rules
allow a maximum of three.
Following their momentous
work, Watson and Crick became
world celebrities. They continued
their research in molecular biology
and received great numbers of
awards and honors. Now that the
structure of DNA was known, the
next big challenge was to solve the
genetic “code.” By 1964, scientists
figured out how sequences of its
bases were translated into the
amino acids that make up specific
proteins and other molecules that
are the building blocks of life.
Today, scientists can identify
base sequences for all the genes of
an organism, collectively known as
its genome. They can manipulate
DNA to move genes around, delete
them from specific lengths of DNA,
and insert them into others. In
2003, the Human Genome Project,
the largest international biological
research project ever, announced
that it had completed the mapping
of the human genome—a sequence
of more than 20,000 genes. Crick
and Watson’s discovery had paved
the way for genetic engineering
and gene therapy. ■I never dreamed that in my
lifetime my own genome
would be sequenced.
James WatsonA DNA molecule is a double helix
formed by base pairs attached to a
backbone made of sugar-phosphates.
The base pairs always match up in
combinations of either adenine–thymine
or cytosine–guanine.Adenine ThymineGuanine CytosineBase pairsSugar-
phosphate
backbone