The Genetics Controversy - Agri-culture: Reconnecting People, Land and Nature - page 128

antibiotic resistance. A range of alternatives is therefore being actively
developed, such as staining, fluorescence and reporter genes.
The biotechnology industry has grown rapidly in both the food and
medical sectors in recent years. The first genetically modified (GM)
products eaten by humans were cheese and tomatoes. GM bacteria were
first used in the early 1990s to produce chymosin, an alternative enzyme
to calf rennet, for vegetarian cheese (the GM bacteria are not eaten). Then,
in 1995, the first year to see commercial cultivation of GM crops
anywhere in the world, tomatoes with their softening gene inactivated,
allowing them to ripen until they reach full flavour and colour without
rotting, were marketed as tomato paste. Since then, the greatest com-
mercial growth has been in crops containing one of two traits. These
comprise, firstly, herbicide tolerance, introduced in soya, oilseed rape,
cotton, maize and sugar beet, which allows the application of broad-
spectrum herbicides to the crop, thereby killing all of the weeds without
damaging the crop. The second trait is insect-resistance through expression
of a gene from the bacterium Bacillus thuringiensis (B.t.) , mainly in maize and
cotton, which means that the B.t. insecticidal toxin is expressed by all cells
of the plant, thereby killing susceptible pests and so reducing the need
to apply some conventional insecticides. By 2001, there were 50 million
hectares worldwide, about three-quarters of which were in the US, and most
of the rest in Canada, Argentina and China. In Europe, small amounts
were commercially grown in France, Spain, Portugal and the Ukraine. 2
New Developments in Medicine and Agriculture
Coinciding with their development in agriculture, these genetic-modification
techniques are also being used in medicine for the study of genes and their
function, and the replacement of genes that cause disease. Gene therapy
will provide opportunities for curing some hitherto untreatable diseases.
One is cystic fibrosis. This affects some 50,000 people worldwide, and
damages their respiratory and intestinal tracts. An inability to clear mucus
from these organs leads to intestinal blockage and recurrent chest infect-
ions, eventually causing respiratory failure. Once the mutated gene
responsible for cystic fibrosis had been identified, this opened the way to
replace the mutant gene with a normal copy, introduced by a vector into
the lungs. Although much research remains to be done, it is now likely
that a complete cure could soon be developed. Other candidates for gene
therapy include muscular dystrophy and heart disease. 3
Molecule 'pharming' is the term used to describe the use of animals
and plants to make pharmaceutical products for medical applications. In