Steve Jones - The Language of the Genes

Now, science has made sex universal. Molecular biology allows genes to be shifted among lineages which were once quite alien to one another; to make recombinant DNA not by the joint efforts of male and female, but by bypassing the inconvenience of reproduction altogether. Genes can be moved from more or less anywhere to anywhere else. At last, DNA can be used where it is needed, wherever it comes from. The biological rules have been broken and a new era of agriculture is at hand.

Genetic engineering began in bacteria, which have a commendable range of sexual interests. They exchange information in many ways; by taking up naked DNA, by a process of mating rather like that of higher animals and by the use of a range of third parties or viruses. This 'infectious heredity' (which suggests that venereal disease evolved before sex) has been subverted by science. The gene to be engineered (which may be from a bacterium, a plant or a human) is put into a piece of viral DNA with the help of various technical tricks. The manipulated virus plus its fellow-traveller is then used to infect a new host. With luck, the recipient will treat the immigrant DNA as its own and make a copy every time its divides. It can be persuaded to generate vast numbers of duplicates of the engineered gene — and large amounts of whatever it manufactures; pure human proteins, drugs, or other materials.

To cross the sexual divide, deep as it is, between bacteria and the rest of life proved unexpectedly easy. Insulin was once extracted from the pancreas of pigs. The human gene was moved to bacteria and large quantities of the pure protein can now be made. Human growth hormone, too — once extracted with much controversy from the pituitary glands of the dead — is now made in the same way. This avoids a macabre and unexpected problem. A few patients caught a nervous degenerative disease from corpses that carried a virus. Now, the factor VIII gene, too, has been inserted into bacteria and patients are treated with its product.

Genetic engineering can also be used against infectious disease. Jenner could use the cowpox virus to vaccinate against smallpox (an experiment which would fall foul of the most lenient Ethics Committee today) because the viruses share antigens, cues of identity recognised by the immune system as the basis of its response. As a result, antibodies against cowpox protect against smallpox. Cow-pox itself can cause problems and even modern vaccines have a small risk of a reaction to the foreign protein. In any case, many diseases {such as leprosy) cannot be helped by vaccination because it is hard to grow their agents in the laboratory.

Some clever engineering gets round the problem. Antigen genes from an agent of disease are inserted into a harmless bacterium, avoiding the risk of infection as the genes for virulence have been left out. Antigens from several sources can be put into the same host to give a single vaccine against many infections. A modified strain of Salmonella {which in its native state can cause food poisoning) is used. The bacterium, with its added antigens, flourishes for a short time in the gut and, by persuading the recipient that he has been infected, ensures that antibodies are made.

Some of the tricks are simple. Plants can make copies of themselves from a few cells so that many can be produced from one without sex. It is hard to improve trees by breeding from the best, because it takes so long. Instead, a superior specimen has its tissues broken into single cells. Copies of that super-tree can then be grown to give, within a single generation, a super-forest. In the same way, natural vanilla, once extracted at great expense from a tropical orchid, has been replaced with the same chemical made by cultures of cells grown in the botanical equivalent of a factory farm.

The real promise for farming comes from inserting genes from one species into another. A certain virus causes what is almost a plant cancer: tissues lose their identity and the plant grows up distorted. This crown gall virus is good at picking up foreign genes and has been used to move them into new hosts. The first transformed plant, a strain of tobacco, was made in 1984, to great lack of public interest. A dozen years later, tomato puree made from engineered plants was on sale without much controversy. Then, though, public alarm began; and the 'Frankenstein Food' label was invented, gathering around itself a variety of cranks who claimed, with no evidence, that such foods were harmful to health.

Part of the problem is the word 'engineering', which sounds more of a threat than does the 'domestication' used of the first genetic manipulators. Part comes from the caution of biologists themselves. Thirty years ago they declared a moratorium (soon abandoned) on new experiments until safety rules were worked out. Most important, people are always suspicious of technical fixes; the idea that science can overcome all problems. From nuclear power to Concorde the optimism of engineers has often turned out to be short-lived. For the companies involved, public concern (helped by their own bland assurances about safety and by simple arrogance in refusing to label engineered food) has proved a real problem. Monsanto makes many things (although it has now changed its name to disguise that faci); but became synonymous with a supposed attempt to poison the public. So alarmed is industry that it has set absurd standards of safety. One project used genes from Brazil nuts put into soybeans to provide a certain amino acid. As this is in short supply in the third world it might have saved thousands of children. Instead the project was abandoned as a very few people are allergic to the nut itself. The new plant might have killed one or two Americans a year. The end of the research was greeted as a triumph by the Greens. Other false accusations turn on the supposed dangers of resistance to an antibiotic, kannamycin, used to help pick out which engineered plants have incorporated foreign DNA. Kannamycin is not used in medicine, is widespread in nature, and its use in genetic manipulation is in any case becoming obsolete. Even so, kannamycin has been used as a stick with which to beat those keen to improve food production.

Other complaints, with more weight than all this pseudo-science, are based on fears about the future of the landscape or of farming itself. Many people do not like modern industrial agriculture (in spite of its productivity) and genetically manipulated foods will, without doubt, help it to prevail. It also, say the opponents, makes little sense to manipulate wheat to add to the grain mountain; or to drive peasants from the land to the cities. The Green Revolution itself forced Indian farmers from the land as large companies gained control of seed production.

Much the same happened half a century ago in the American mid-West. In the 1930s new strains of hybrid corn were made by crossing two lineages together. Their sale was controlled by combines who manipulated the price and put small farmers out of business. Another commercial trick played a part. No longer could a producer use his own seed for the following year because a hybrid plant produces new and unfavourable mixtures among its offspring. Engineered seeds pose the same danger of a harvest of the grapes of economic wrath. Few farmers can bargain with an organisation with a monopoly on the sale of a herbicide-tolerant plant — and the herbicide involved. The companies have threatened ro sue those who plant the new seeds in a subsequent year without a new purchase (and have been sued in their turn by clients disappointed by its yield and by others whose own crops are polluted by manipulated pollen). New 'terminator technology' prevents engineered plants from setting seed and — as in the mid-West — forces those who use them to buy new stocks for every harvest.

As is often the case in genetics, much more has been promised by biotechnology than has been achieved (particularly in the third world, where few profits are to be made). Some GM crops have lower yields than others, which has led some farmers to give them up. Such is the storm generated by their use that their potential may be long delayed. Thirty million hectares of land were planted with GM crops in 1998; and a million Chinese farmers used engineered cotton. So alarmed is the public (and so over-priced the seeds) that in the west at least the acreage has been reduced since then.