onstrated independently by Jeff Schell and Marc Van
Montagu (University of Ghent), Mary-Dell Chilton
(Washington University), Eugene Nester (Univer-
sity of Washington), and Rob Horsch (Monsanto)
that the Ti plasmid fromAgrobacterium tumefaciens
could transfer genes into tobacco plants by deleting
from the plasmid the genes required for tumor pro-
duction and replacing them with foreign genes to be
transferred. Now plants could be genetically modi-
fied not only by radiation and chemicals but also by
introducing genes from other species. By 1984, Ingo
Potrykus at the Swiss Federal Institute of Technology
(Zurich) produced the first evidence that foreign
genes could be transferred into plants, opening the
door to plant genetic engineering.
Genetically Engineered Food Plants Although it
contained no foreign genes, the first genetically en-
gineered food product to come to market was the
Flavr Savr tomato, developed by Calgene (subse-
quently purchased by Monsanto) in 1993. The Flavr
Savr tomato could be vine-ripened but would not
soften as quickly as other tomatoes, allowing it to be
shipped around the country without being as easily
damaged. Calgene withdrew the Flavr Savr tomato
from the market in 1996 due to high production
costs.
Robert Fraley and Stephen Rogers from Mon-
santo and Roger Beachy from Washington Univer-
sity were the first to genetically engineer plants to
be disease-resistant. The scientists inserted a pro-
moter, a piece of DNA necessary for a gene to func-
tion, from the cauliflower mosaic virus (CaMV) and
the coat protein gene from tomato mosaic virus
(ToMoV) into tomato plants, thereby making them
resistant to ToMoV. Using this technology, Mon-
santo brought virus-resistant squash seeds to market
in 1994 followed by virus-resistant seeds of canta-
loupes, potatoes, and papayas.
In an effort to increase yield and decrease the use
of pesticides, many crop plants were engineered in
the 1990’s to resist various herbicides such as glypho-
sate, the active ingredient in Roundup. Other plants
were engineered to produce a natural insecticide by
inserting from the bacteriumBacillus thuringiensis
theBtgene that codes for a protein toxic to insect
larvae. These genetically modified plants are known
asBtplants. By the end of the 1990’s, theBtgene had
been transferred to cotton, tobacco, tomato, potato,
and corn plants. In the United States, genetically al-
tered soybeans, corn, squash, canola, flax, papaya,
chicory, sugar beets, tomatoes, and potatoes have
been developed and approved as food crops. Cot-
ton, although not a food crop, has also been ap-
proved.
At the 1984 meeting of the International Rice Re-
search Institute in the Philippines, Peter Jennings of
the Latin American Fund for Irrigated Rice sug-
gested that genes that would allow rice to synthesize
vitamin A should be engineered into rice plants to
enrich their nutritional value. The Rockefeller
Foundation funded several studies by many scien-
tists beginning in 1990 that led to the incorporation
of vitamin A-synthesizing genes from daffodils into
rice. By 1999, Ingo Potrykus and Peter Beyer had ge-
netically engineered vitamin A-producing Golden
Rice, a crop that proponents argue could improve
the vitamin A-deficient diets of people in developing
nations.
Approval Process for Altered Crops In the United
States, all GM crops must be evaluated for safety and
approved by at least two (and often three) govern-
ment agencies: the U.S. Department of Agriculture
(USDA), the Environmental Protection Agency
(EPA), and the Food and Drug Administration
(FDA). Only crops modified by molecular means are
subject to the approval processes. Crops modified by
radiation or by conventional breeding methods,
even though they may contain genes from different
species or genera, do not need to go through the ap-
proval process. These requirements for approval
stem from the public’s fear that genetically engi-
neered crops may either be harmful to one’s health
or upset the balance of nature and cause environ-
mental harm.
Controversy Although genetically altered foods
such as triticale, a laboratory-created food plant
that contains genes from wheat and rye, two unre-
lated species, have been commercially grown for
years, the introduction of genetically engineered
food plants caused a firestorm of controversy. The
controversy developed in the early 1990’s, when
Pam Dunsmuir and her colleagues at DNA Plant
Technology Corporation introduced an Arctic
flounder gene (which depresses the freezing point
of water) into a tomato in an attempt to protect del-
icate tomato plants from subfreezing tempera-
tures. Although the tomato was never brought to
market, the experiment became a focal point for362 Genetically modified foods The Nineties in America