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note, viruses essentially do the same thing as biotechnologists. They insert
their DNA into the DNA of the host they are infecting and cause the host cell
to produce viral-DNA products, which are the proteins needed to make viral
components. This ability of viruses to transfect cells is used in transgenic
technology where specific genes desired to be inserted into a chromosome are
delivered by a bioengineered virus. It is also similar to a mechanism whereby
a drug-resistant bacteria can transmit the genes conveying resistance to
another bacteria. RNA viruses can take some shortcuts and even be more effi-
cient at invading host cells and usurping control of the genetic machinery. As
will be seen in the final chapter, treating viral infections is an extremely com-
plicated task since we must kill organisms that have taken control of genetic
machinery in our own cells. They are not like insects or bacteria that have an
independent life with unique biochemical targets; instead they are more anal-
ogous to a computer program occupying the very computer that we must use
to eliminate them.
The study of the structure and function of DNA, as well as its applications
to biotechnology, is termed genomics. The study of the resulting proteins that
are produced is termed proteomics. The cracking of the human genetic code
has led to great investments into attempting to manipulate human DNA to
cure disease by either deleting genes which produce adverse effects or adding
genes to produce products that are lacking in the diseased genome, for exam-
126 CHAPTER 9
ple, insulin or growth hormone production. The approach of twentieth cen-
tury science was to administer the missing protein by injection; the promise
of twenty-first century science will be to insert the gene that codes for this
protein and let the cell do the rest.
DNA is truly analogous to a computer program consisting of instructions
to accomplish a task. Computers can be the same, but they might do very dif-
ferent things depending on what the program commands. Biotechnology uses
the same process and slips a specific gene that codes for different proteins
into the plant chromosomes. This was first employed by creating a genetical-
ly engineered strain of corn that produced a specific enzyme in the root of the
plant. This specific enzyme was deadly to a major pest of corn, the European
corn borer. This insect is attributed with causing $1 billion in annual crop loss
in the United States alone. The enzyme, specifically named Cry9C, belongs to
a class of poisonous proteins known as delta endotoxins. The genetic infor-
mation to code for this poison is obtained from the bacteria Bacillus
thuringiensis (Bt for short). Such genetically modified corn is thus termed Bt
Corn. As a result of this development, chemical pesticides should not be
needed to kill the European corn borer. Additionally, elimination of the borer
may decrease opportunistic fungal infection which invade the weakened plant
that themselves may be associated with mycotoxin production. Since the Bt
toxins are proteins, they, like the rest of the plant, will degrade in the envi-
ronment after the corn is harvested.
Similar strategies have also been applied to potato, cotton, and soybean
crops, conferring resistance to insect pests as well as inserting genes that make
them resistant to the effects of herbicides. This allows farmers to spray fields
with a chemical such as Roundup® without killing the crop being raised. In
2001, it is estimated that approximately 26% of corn acreage, 68% of soybean,
and 69% of cotton raised in the United States will use genetically modified
seeds. Some products are being designed which increase the production of
nutrients and anticarcinogenic substances naturally found in vegetables in an
attempt to increase their benefits even more. Food crops such as sorghum and
millet, staples for much of starving Africa, are difficult to grow because of sus-
ceptibility to the parasitic Witchweed, Strigia. Bioengineered sorghum resist-
ant to Strigia would significantly reduce starvation. Arguably the most prom-
ising bioengineered plant, one that symbolizes the potential benefits of trans-
genic technology, is golden rice. This is rice which is genetically engineered
to produce vitamin A and which also confers a golden hue to the resulting
rice. Rice is the staple of much of the developing world but lacks vitamin A.
It has been estimated that up to 2 million children die each year from this defi-
ciency. Another half a million may go blind.
Are these products safe? Critics suggest that inserted gene products may be
toxic to humans or other beneficial insects eating these crops. However, com-
BIOTECHNOLOGY AND GENETICALLY MODIFIED FOODS 127
pared to the older practices of breeding, this is unlikely since only specific
genes are being inserted. With traditional breeding, whole chromosomes
were being selected that may have carried adverse genes for the ride. We dis-
cussed some such toxic potatoes and celery in Chapter 3.
The first transgenic plant ever introduced into the American market was the
Calgene FlavrSavr® tomato, which underwent voluntary FDA safety testing
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