Biologists try to allay fears regarding genetic research

Biologists who are deciphering the genetic blueprints of living organisms are concerned about the general public's continuing fears regarding their work. Such apprehension, as expressed in the June 8 petition from 56 US religious leaders asking Congress to halt genetic tampering with human germ cells, could hamper what these biologists consider some of the most fruitful work their science has ever produced.

A recent gathering of theologians and scientists in New Hampshire took a more moderate stance. A paper summarizing findings of that conference, which was sponsored by the Institute on Religion in an Age of Science, cautioned that genetic research should be carried on with ''extreme regard for potential risk to the future person.'' But it also called a curb on such research ''unnecessary and misleading.''

Biochemist Harold C. Slavkin of the University of Southern California has now issued a statement trying to put this work in a realistic perspective. He explains that, far from seeking to redesign human beings, most genetic engineering research has one of three aims - understanding how genes work, tracing organic evolution at the molecular level, or producing useful biochemical substances. The latter chemicals include drugs such as human insulin or, in the case of Slavkin's own work, tooth enamel, which would be produced by bacteria as a dental aid.

Such research is proceeding so fast that you have only to look at the latest news reports to find pertinent examples.

In the area of gene operation, the Lawrence Berkeley Laboratory of the University of California has just announced the deciphering of five genes responsible for key steps in photosynthesis. These genes, found in bacteria, have turned out to be identical to those of higher plants. This shows that, over the 3 billion of years of evolution separating the bacterium and a plant like spinach, genetic instructions basic to photosynthesis have remained unaltered and have spread widely throughout the plant kingdom.

At this stage, such knowledge is mainly of basic scientific interest. Yet it is also the kind of knowledge agricultural biologists will one day need if they are to continue to improve crop plants.

This illustrates Slavkin's point that the techniques that some people fear might be misused to redesign humans are actually essential tools for developing beneficial knowledge. At the Lawrence Berkeley Laboratory, the research team - John E. Hearst, Douglas C. Youvan, Marie Alberti, Helmut Begusch, Edward J. Bylina, and Kristina Zsebo - ''tampered'' directly with the genetic material of the bacteria in order to locate and decode the photosynthesis genes.

To explain it very briefly, a gene is a set of biological information which, like a section of a blueprint or a chemist's formula, specifies the design of a given protein. The protein made according to this design by a living cell - in this case the bacterium Rhodopseudomonas capsulata found in sewage lagoons and along lake shores - carries out some specific biochemical function. The genetic information is encoded as part of the structure of a DNA molecule which the bacterium carries and transmits to its offspring.

Deciphering such a message is a little like reading Morse code. The dots and dashes of Morse code are used in various combinations to represent letters. The genetic code uses combinations of four different chemical units called bases, taken three at a time.

Each combination of three bases specifies a particular amino acid. The amino acids are chemical compounds that are building blocks of proteins. Thus the sequence of DNA bases, taken three at a time, specifies the sequence of amino acids that make up a protein.

The trick in ''reading'' such a DNA message is knowing where to start along the sequence of hundreds of thousands of bases in a typical DNA molecule. The Berkeley team was able to locate precisely where the information for the photosynthesis genes lies along the bacterial DNA sequence.

They used genetic engineering techniques to cut up the bacterial DNA and recombine the pieces. They also compared proteins produced according to the instructions of the natural DNA material with those corresponding to their interpretation of the photosynthesis genes. In this way, they confirmed their translation of the genetic message.

Such techniques are fundamental to the new biology. They enable geneticists to decode genetic ''messages'' and gain a deeper knowledge of plants and animals. Yet they are the same techniques that one day could conceivably be misused to redesign the human germline.

Consider another example. Human beings and many other animals have structures in their cells called mitochondria, which contain a special form of DNA. This particular DNA is inherited exclusively from the mother. Scientists are often able to trace the mitochondrial DNA in a given group of animals back to individual mothers and to determine the race of those ancestral mothers. This can also be done with people if there has not been significant intermarriage outside the group.

In a typical application of this kind of research, the Australian News Service reports that scientists at the University of New South Wales and the Australian National University are tracing the ancient migrations of Australian Aboriginals. By decoding the mitochondrial DNA of living Aborginals, the scientists can link their ancestors with people from parts of Southeast Asia and Indonesia.

Here again, the techniques used to study the mitochondrial DNA are techniques of genetic engineering. Fear-inspired thinking would restrict, or even ban them, as being potentially subject to misuse. But this is neither rational nor wise.

Slavkin is right when, reflecting the outlook of many of his colleagues, he points out: ''Recombinant DNA technology is a tool, no more moral or immoral than electricity, fire, or the hammer. Let's not allow misguided fear to deny its benefits to ourselves and posterity.''

This fear is largely a fear of the unknown. There is wisdom in discussing the moral and political implications of the new biology now before they are even ready to be applied to humans, if that were ever desirable. But for Congress to restrict the new research at this stage just because of a vague concern over possible misuse would be foolish.