b'When DNA Come Out to PlayWOW! LOOK AT MY DNA!the exuberant littleCrick and Watson unraveled the molecular structure boy blurted out as he pulled the thread-like strandsof DNA, the molecule that controls the inner workings out of the test tube. Soon other excited voices chimedof the cell. The instructions for everything a cell does in as about two dozen children and a sprinkling ofare encoded in genes which are specific fragments adults began to play with their own genetic material.of DNA. Basically, genes tell the cell what proteins to We were all seated around tables in a laboratory atproduce. Proteins are needed as structural material the American Museum of Natural History in New York,and as enzymes, the catalysts that control all reactions having been attracted by signs pointing towards thein a cell. Once DNAs role was clearly understood, it Gene Scene. Our experiment started with everyonebecame obvious that if its structure could be modified, JOE SCHWARCZswirling salt water in their mouth for thirty seconds orthe proteins it produced could be altered. By the 1970s is director of McGillso to collect some of the cells that are continuouslysuch manipulation, known as genetic engineering, had University Office forsloughed off by our cheeks. We were then asked tobecome a possibility. Genes could be transferred from Science and Society inspit the solution into a little cup (and then transfer it toone organism to another or could even be built from Montreal, QC, Canada. a test tube containing some detergent.fundamental components using the Gene Machine. A couple of minutes of gentle shaking allowed theWe are now beginning to see some of the practical detergent to break down the cell membranes and liber- results of this genetic tinkering. For example, cheese ate the DNA molecules which were then solidified bymaking requires an enzyme called chymosin to sepa-the addition of alcohol. We then dipped a stirring rodrate the curds from the whey. The traditional source is into the test tube and pulled out long filaments of DNA.the stomach lining of calves, but the gene, which tells As the session drew to a close, the children were askedthe cell to produce this enzyme, has now been isolated. what they had learned. There were some pretty goodIt can be incorporated into the DNA of a yeast which answers but the one that really stuck in my mind wasthen dutifully cranks out chymosin. This has made provided by the little boy who had cried out so enthusi- cheese production more efficient. Much more dramatic astically when he first glimpsed his DNA. What he hadis the potential treatment of people who suffer from learned, he said, was that when he grew up, he wantedspecific immune system deficiencies due to a malfunc-to study biotechnology and become a genetic engi- tioning gene. Already in one case, bone marrow has neer! Quite a refreshing comment given that so manybeen extracted, the malfunctioning gene replaced, people these days look warily on this area of science.and the marrow infused back into the bone. This has The raised eyebrows can often be traced to a lack ofresulted in the production of cells with normal genes. clear understanding of what biotechnology is all about.These days insulin for diabetics is cranked out by Simply put, biotechnology is the provision of usefulbacteria to which the human insulin gene has been products and services from biological processes. Ittransferred. Bacteria also have been engineered to does not necessarily involve scientists in white labproduce TPA (tissue plasminogen activator) which has coats hovering over Petri dishes. In fact, biotechnologysaved countless lives when administered after a heart goes back thousands of years, probably to the firstattack to dissolve blood clots. Before the genetic engi-use of yeast to convert sugars and starches to alco- neering, TPA was produced by fermentation and was hol. Molds are also neat little machines that producevery expensive.a variety of by-products. When the ancient EgyptiansBy the time the little guy who had been wowed put moldy bread as a poultice on wounds, they wereby the experiment at the museum, grows up, genetic using biotechnology. The mold probably churned outengineering will have produced wonders. As he wan-penicillin, not recognized as such of course, and helpeddered off, I noted that he stuffed his DNA sample into the wound heal.the back pocket of his jeans. Jeans that may have been How these microbes convert raw materials intodyed with indigo produced by recombinant DNA and finished products was not elucidated until relativelymade of cotton genetically engineered to repel insects recent times. The pivotal moment came in 1953 whenwithout the need for pesticides.SWSEED ASSOCIATION OF THE AMERICAS 2022SEEDWORLD.COM /9'