b'SENSE, NONSENSE AND SCIENCEBY: JOE SCHWARCZWHEN DNA COME OUT TO PLAYW ow! Look at my DNA! thesugars and starches to alcohol. Moulds areproteins it produced could be altered. By exuberant little boy blurtedalso neat little machines that produce athe 1970s such manipulation, known as out as he pulled the thread- variety of by-products. When the ancientgenetic engineering, had become a pos-like strands out of the test tube. SoonEgyptians put mouldy bread as a poulticesibility. Genes could be transferred from other excited voices chimed in as abouton wounds, they were using biotechnology.one organism to another or could even be two dozen children and a sprinkling ofThe mould probably churned out penicil- built from fundamental components using adults began to play with their own geneticlin, not recognized as such of course, andthe Gene Machine,. material. We were all seated around tableshelped the wound heal.We are now beginning to see some of in a laboratory at the American Museumthe practical results of this genetic tinker-of Natural History in New York, havinging. For example, cheese making requires been attracted by signs pointing towardsan enzyme called chymosin to separate the Gene Scene. Our experiment startedthe curds from the whey. The traditional with everyone swirling salt water in theirsource is the stomach lining of calves, but mouth for thirty seconds or so to collectthe gene, which tells the cell to produce some of the cells that are continuouslythis enzyme, has now been isolated. It can sloughed off by our cheeks. We were thenbe incorporated into the DNA of a yeast asked to spit the solution into a little cupwhich then dutifully cranks out chymo-(and then transfer it to a test tube contain- BIOTECHNOLOGYsin. This has made cheese production ing some detergent.GOES BACKmore efficient. Much more dramatic is the A couple of minutes of gentle shakingpotential treatment of people who suffer allowed the detergent to break down theTHOUSANDS from specific immune system deficiencies cell membranes and liberate the DNA mol- OF YEARS. due to a malfunctioning gene. Already in ecules which were then solidified by theone case, bone marrow has been extracted, addition of alcohol. We then dipped a stir- the malfunctioning gene replaced, and the ring rod into the test tube and pulled outmarrow infused back into the bone. This long filaments of DNA. As the session drewhas resulted in the production of cells with to a close, the children were asked whatnormal genes. they had learned. There were some prettyThese days insulin for diabetics good answers but the one that really stuckis cranked out by bacteria to which the in my mind was provided by the little boyhuman insulin gene has been transferred. who had cried out so enthusiasticallyBacteria also have been engineered to when he first glimpsed his DNA. What heHow these microbes convert rawproduce TPA (tissue plasminogen acti-had learned, he said, was that when hematerials into finished products was notvator) which has saved countless lives grew up, he wanted to study biotechnol- elucidated until relatively recent times.when administered after a heart attack ogy and become a genetic engineer! QuiteThe pivotal moment came in 1953 whento dissolve blood clots. Before the genetic a refreshing comment given that so manyCrick and Watson unravelled the molec- engineering, TPA was produced by fer-people these days look warily on this areaular structure of DNA, the molecule thatmentation and was very expensive.of science. The raised eyebrows can oftencontrols the inner workings of the cell.By the time the little guy who had be traced to a lack of clear understandingThe instructions for everything a cell doesbeen wowed by the experiment at the of what biotechnology is all about.are encoded in genes which are specificmuseum, grows up, genetic engineering Simply put, biotechnology is the pro- fragments of DNA. Basically, genes tell thewill have produced wonders. As he wan-vision of useful products and services fromcell what proteins to produce. Proteinsdered off, I noted that he stuffed his DNA biological processes. It does not necessar- are needed as structural material and assample into the back pocket of his jeans. ily involve scientists in white lab coatsenzymes, the catalysts that control allJeans that may have been dyed with indigo hovering over Petri dishes. In fact, bio- reactions in a cell. Once DNAs role wasproduced by recombinant DNA and made technology goes back thousands of years,clearly understood, it became obviousof cotton genetically engineered to repel probably to the first use of yeast to convertthat if its structure could be modified, theinsects without the need for pesticides.EUROPEAN-SEED.COMIEUROPEAN SEED I 25'