322
INSERT GENES
INTO HUMANS TO
CURE DISEASE
WILLIAM FRENCH ANDERSON (1936–)
T
he human genome—the
entirety of a human’s
hereditary information—
consists of about 20,000 genes.
A gene is a living organism’s
molecular unit of heredity.
However, genes often malfunction.
A defective gene is made when a
normal gene is not copied properly,
and the “error” is passed down from
parents to offspring. The symptoms
that arise from these so-called
genetic diseases depend upon
the gene involved. A gene works
by controlling the production of a
protein—one of many that perform
a vast variety of functions in living
organisms—but this production
fails if there is an error. For
example, if a blood-clotting gene
malfunctions, the body stops
producing the blood protein that
makes blood clot—causing the
disease hemophilia.
Genetic diseases cannot be
cured by conventional drugs, and
for a long time, it was only possible
to alleviate the symptoms and
make a sufferer’s life as comfortable
as possible. But in the 1970s,
scientists began considering the
possibility of “gene therapy” to cure
disease—using “healthy” genes to
replace or override faulty ones.IN CONTEXT
BRANCH
BiologyBEFORE
1984 US researcher Richard
Mulligan uses a virus as a tool
for inserting genes into cells
taken from mice.1985 William French
Anderson and Michael Blaese
show this technique can be
used to correct defective cells.1989 Anderson performs the
first safety test in human gene
therapy, injecting a harmless
marker into a 52-year-old man.
He performs the first clinical
trial a year later.AFTER
1993 UK researchers describe
the results of successful
animal experiments providing
gene therapy treatment of
cystic fibrosis.2012 The first multidose trial
of cystic fibrosis gene therapy
on humans begins.Genes can be
transferred between
cells by using vectors:
viruses or rings of DNA
called plasmids.Many diseases are
inherited and are caused
by defective genes.Functional genes
can be isolated from
normal cells using enzymes
that cut DNA.Genes can be inserted
into humans to
cure disease.