Hoffman La Roche, which specialises in drugs and diagnostics, owns a majority stake in a leading US biotechnology firm, Genentech, based in Palo Alto, California, and supplies venture capital to smaller biotech start-up firms through its Roche Bioscience subsidiary.

The company has recently launched two genetically engineered drugs in the US and Europe: Zenapax, which prevents rejection of kidney transplants, and MabThera, which helps treat Hodgkin's lymphoma, a kind of cancer.

Roche has also become the world leader in diagnostics, paying $11bn to acquire the Corange group and its German subsidiary Boehringer Mannheim. Many of their products are also a result of genetic engineering.

Roche had sales of $12,8bn in 1997 and employed 51,600 people world-wide.

Genetically engineered corn is causing controversy

Even larger is Novartis, a $27bn company formed by the merger of Ciba-Geigy and Sandoz. Novartis ranks number 3 in the world in prescription drugs (after Merck and Glaxo), which make up 40% of its business. It is also a leader in agribusiness, nutrition (including Gerber baby foods), and opthalmics. It had total sales of $21.3bn last year with 87,000 employees.

Novartis is particularly vulnerable to concern over genetic engineering because of its agribusiness division, the world's largest. It makes a genetically engineered corn, for example, which is resistant to the European corn borer, a larvae which can destroy up to 20% of the corn crop.

The company also uses transgenic (genetically modified) animals for testing the effectiveness of drugs, which it says reduces the need for laboratory animals.