Nature Altered for Aussie Farmers `Super Pigs' Are One Result of an Aggressive Program to Modify Genes for Agricultural Benefits. GENETIC ENGINEERING

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TO kill weeds, wheat farmers in Australia spray the herbicide 24D. Unfortunately, the herbicide also kills cotton plants, which are often planted in nearby fields.

By genetically modifying the cotton plant, however, scientists at the Commonwealth Scientific and Industrial Research Organization (CSIRO) have increased the cotton's tolerance to the herbicide almost 50 times. Next year, CSIRO will begin field-testing the altered plant.

The cotton modification is one of several ways Australia is working to improve its farms with genetic engineering.

"This is powerful technology, and it is an area in which Australian science is in many cases one jump ahead of the rest of the world," says John Stocker, chief executive of CSIRO.

The Genetic Manipulation Advisory Committee (GMAC), a private clearinghouse, has approved seven genetically modified organisms for use in Australia. Many more genetic modifications are being developed in the laboratories and will soon be field-tested. Although there are no national numbers on the amount spent on genetic research, CSIRO estimates it is now spending annually $32 million (US), or 7 percent of its total budget, on genetic research. CSIRO, a mainly government-funded research arm, is the largest science organization involved in the research.

Some of the most fundamental research is taking place at the University of Adelaide, where scientists are trying to control the activity of any gene that can be placed in an animal. For example, scientists know that growth hormones help livestock grow.

"The question is, can we put in a gene that will do the job instead of administering the growth hormone externally," says Julian Wells, director of the Special Research Center in Gene Technology at the university.

The first animals Dr. Wells worked on are pigs, termed "super pigs" because of their ability to grow more efficiently and have less fat than normal pigs. Wells says super pigs are still five to 10 years away from being commercially available. "It is important to get it right before commercialization," he says.

Many modifications involve Australia's main crops - wheat and wool. In July, GMAC approved a CSIRO "tracking" technique for genetically tagging soil bacteria that can reduce take-all disease in wheat. Take-all can decrease wheat yields by more than 50 percent, depending on the weather. Although the soil bacteria is natural, the scientists needed to see if it would migrate into the water supply or to other areas. As a result of the genetic tagging, CSIRO reported, "There is little chance of it moving into the water system or affecting other soil processes."

A professor at the University of Adelaide is now trying to change the genes of sheep so they produce more wool. To grow wool, a sheep needs sulfur. Much of the sulfur in its food is digested in a pre-stomach, however, and is not available to the animal. By changing a gene, scientists hope to allow the sheep to use more sulfur. This process has not been cleared with GMAC for release but is being tested on laboratory mice. At the same time, scientists are trying to increase the amount of sulfur produced by alfalfa, known as lucerne in Australia.

Sheep growers also have a problem with the salmonellosis virus when shipping live sheep for export. "Exporters have lost 1/3 of their sheep," says Merilyn Sleigh, assistant chief at CSIRO's division of biomolecular engineering in North Ryde, a Sydney suburb. Through genetic manipulation, CSIRO's McMaster Laboratory has produced a vaccine for the sheep. Ms. Sleigh says the initial test was successful and the vaccine has been cleared by GMAC for release. Australian scientists have also genetically modified a virus used for vaccinating cattle to prevent feedlot animals from getting bovine rhinotracheitis, a respiratory disease. …