1 00:00:00,000 --> 00:00:10,271 In ultraviolet light, a technician purifies the very essence of life. 2 00:00:10,271 --> 00:00:13,276 Scientists have acquired profound new abilities. 3 00:00:13,276 --> 00:00:19,284 They can read the secret code of life and change its genetic structure. 4 00:00:19,284 --> 00:00:22,288 The greatest mysteries may soon be solved. 5 00:00:22,288 --> 00:00:27,295 We could discover how a human being develops from a single egg. 6 00:00:27,295 --> 00:00:31,301 We might even find out what causes life. 7 00:00:31,301 --> 00:00:40,313 Music 8 00:00:40,313 --> 00:00:46,322 Beyond the outer planets of our solar system, space curves off into the vast abyss of the universe. 9 00:00:46,322 --> 00:00:53,332 Scientists believe our universe exploded into being some 15 billion years ago. 10 00:00:53,332 --> 00:00:59,340 It formed countless galaxies of 100 billion stars. 11 00:00:59,340 --> 00:01:03,346 On our planet, life developed over 3 billion years. 12 00:01:03,346 --> 00:01:07,351 It evolved from simple virus-like particles to plants, animals, 13 00:01:07,351 --> 00:01:14,361 and the incredibly complex organism that is man. 14 00:01:14,361 --> 00:01:20,370 Since the dawn of history, people have wondered, what is the essence of life? 15 00:01:20,370 --> 00:01:24,375 Music 16 00:01:24,375 --> 00:01:31,385 Several hundred years ago, pioneers with microscopes discovered the basic building block of life, the cell. 17 00:01:31,385 --> 00:01:33,388 Cells are the primary unit of life. 18 00:01:33,388 --> 00:01:37,393 100 trillion cells comprise a human being. 19 00:01:37,393 --> 00:01:46,406 Billions of muscle cells, skin cells, nerve cells, and blood cells all working together to orchestrate our every movement. 20 00:01:46,406 --> 00:01:54,417 The most remarkable ability of the cell is its capacity to grow and divide. 21 00:01:54,417 --> 00:02:04,431 Fertilized egg cells begin the process of development that in 21 days will culminate in the birth of baby mice. 22 00:02:04,431 --> 00:02:08,437 What marvelous control system governs this miracle of growth? 23 00:02:08,437 --> 00:02:15,447 What mysterious forces cause the development of a heart? 24 00:02:15,447 --> 00:02:22,456 Since the early 1950s, the science of biology has undergone a revolutionary change. 25 00:02:22,456 --> 00:02:28,465 Scientists have begun to unravel the innermost secrets of the cell. 26 00:02:28,465 --> 00:02:32,470 Within each cell are tiny structures called chromosomes. 27 00:02:32,470 --> 00:02:37,477 They contain the information cells need to live and grow. 28 00:02:37,477 --> 00:02:43,486 Just before cells divide, these chromosomes copy themselves exactly. 29 00:02:43,486 --> 00:02:50,496 They transmit the blueprint of life from generation to generation. 30 00:02:50,496 --> 00:02:55,503 The chromosomes are composed of thousands of incredibly small units called genes. 31 00:02:55,503 --> 00:03:03,514 The genes order the cell to make molecules which are vital to life. 32 00:03:03,514 --> 00:03:07,520 Genes are made of a molecule called DNA. 33 00:03:07,520 --> 00:03:11,525 Its twisted strands store the genetic information in a simple code. 34 00:03:11,525 --> 00:03:17,534 DNA is composed of only four chemical units endlessly repeated in various combinations. 35 00:03:17,534 --> 00:03:24,543 The magic of DNA is how these simple units determine all the forms of life we know. 36 00:03:24,543 --> 00:03:30,552 The wonder of DNA is most obvious in the phenomenal likeness of identical twins. 37 00:03:30,552 --> 00:03:36,560 Each girl has inherited precisely the same set of genetic instructions. 38 00:03:36,560 --> 00:03:43,570 They are what they are because of some hundred thousand genes written in the language of DNA. 39 00:03:43,570 --> 00:03:52,583 So incredibly precise is this genetic code that Lisa and Ingrid are alike down to their freckles and the tiny nicks on their ears. 40 00:03:52,583 --> 00:03:58,591 As scientists expand their knowledge of the code of life, it is becoming easier to change life. 41 00:03:58,591 --> 00:04:01,595 To alter is genetic structure. 42 00:04:01,595 --> 00:04:05,601 Chromosomes, genes and DNA are tiny chunks of matter. 43 00:04:05,601 --> 00:04:10,608 They can be engineered, cut up and rearranged in endless combinations. 44 00:04:10,608 --> 00:04:15,615 The technology can be developed, some of it already exists. 45 00:04:15,615 --> 00:04:19,620 In dealing with human life, biologists are much more limited. 46 00:04:19,620 --> 00:04:24,627 Once a child is born, its genetic structure is fixed, unchangeable. 47 00:04:24,627 --> 00:04:29,634 If the genetic instructions are faulty, little can be done. 48 00:04:29,634 --> 00:04:33,640 The adult could be a crippling disease. 49 00:04:33,640 --> 00:04:39,648 It is possible, however, to detect some genetic defects during pregnancy. 50 00:04:39,648 --> 00:04:46,658 Because her risk increases with age, this woman has decided to have a test. 51 00:04:46,658 --> 00:04:51,665 An obstetrician withdraws some fluid from the sac surrounding the growing fetus. 52 00:04:51,665 --> 00:04:58,675 In the fluid are a few of its cells. 53 00:04:58,675 --> 00:05:06,686 The cells are added to a nutrient broth in which they can live and grow. 54 00:05:06,686 --> 00:05:14,698 Placed in an incubator, the cells multiply until there are enough for the test. 55 00:05:14,698 --> 00:05:19,705 A technician searches for cells in which the chromosomes are easy to see. 56 00:05:19,705 --> 00:05:22,709 She checks the size and shape of each one. 57 00:05:22,709 --> 00:05:27,716 In this case, the chromosomes looked perfectly normal. 58 00:05:27,716 --> 00:05:34,726 However, when the genetic structure of healthy cells is damaged, the result may be cancer. 59 00:05:34,726 --> 00:05:41,735 Normal genes switch off while malignant genes switch on. 60 00:05:41,735 --> 00:05:50,748 Renegade cells grow out of control. They invade the tissues around them and form tumors. 61 00:05:50,748 --> 00:05:55,755 The fast growing tumor on this mouse's back will rapidly kill it. 62 00:05:55,755 --> 00:06:00,762 At the Lawrence Livermore Lab, some of the tumor cells are removed. 63 00:06:00,762 --> 00:06:04,768 Their DNA is stained with a special dye. 64 00:06:04,768 --> 00:06:09,775 When the blue laser beam hits the DNA, it causes tiny flashes of light. 65 00:06:09,775 --> 00:06:12,779 These flashes are detected electronically. 66 00:06:12,779 --> 00:06:20,790 Their pattern is typical of cancer cells which have more DNA than normal cells. 67 00:06:20,790 --> 00:06:25,797 The scientists have another extremely sensitive way to check chromosomes. 68 00:06:25,797 --> 00:06:36,812 An electronic scanner hooked up to a computer forms pictures which show the precise amount of DNA in each chromosome. 69 00:06:36,812 --> 00:06:46,826 So exact is this system that it tells the difference between chromosomes inherited from the mother and those from the father. 70 00:06:46,826 --> 00:06:54,838 With such computerized technology, we begin our journey into advanced genetic research. 71 00:06:54,838 --> 00:07:03,850 To probe the mysteries of cell division, a powerful laser beam is used to perform surgery on cells and chromosomes. 72 00:07:03,850 --> 00:07:13,864 Dr. Michael Burns of the University of California at Irvine has developed this remarkable technique of genetic engineering. 73 00:07:13,864 --> 00:07:24,880 The lens focuses the laser light into a tiny beam which cuts through cells like a microscopic scalpel. 74 00:07:24,880 --> 00:07:37,898 The beam is so precise that it can be aimed at individual chromosomes and even used to snip off pieces containing a few genes. 75 00:07:37,898 --> 00:07:46,911 Dr. Burns finds two chromosomes and hits them with the laser. 76 00:07:46,911 --> 00:07:54,922 The cell is not destroyed. It continues to divide, but the chromosomes hit by the laser are expelled. 77 00:07:54,922 --> 00:07:58,927 Their messages will not be passed on to other cells. 78 00:07:58,927 --> 00:08:06,939 What comes next is another amazing feat of microsurgery, the manipulation of cells a thousandth of an inch across. 79 00:08:06,939 --> 00:08:14,950 Carefully, all the cells around the one hit by the laser are scraped away. 80 00:08:14,950 --> 00:08:20,958 A nutrient fluid is added so that the single cell remaining can reproduce itself. 81 00:08:20,958 --> 00:08:29,971 Over the next few weeks, that single cell will divide into a colony of identical cells. 82 00:08:29,971 --> 00:08:40,986 Mysteriously, the destroyed chromosome is replaced by the remaining ones, thus restoring normal chromosome number to the cells. 83 00:08:40,986 --> 00:08:46,995 Other biologists have developed more precise techniques of genetic engineering. 84 00:08:46,995 --> 00:08:55,006 They can chop DNA molecules into pieces without destroying the molecules' ability to play the game of life. 85 00:08:55,006 --> 00:09:05,020 If they could link up these pieces in the right combination, they might solve the mysteries of the gene. 86 00:09:05,020 --> 00:09:16,035 If they could insert bits of DNA into living cells, they could create forms of life with new genetic structures. 87 00:09:16,035 --> 00:09:21,042 Their testing ground has been a tiny bacterium called E. coli. 88 00:09:21,042 --> 00:09:27,051 It lives in the human intestine where its functions are largely unknown. 89 00:09:27,051 --> 00:09:41,070 The molecular biologists have found a way to splice genes from animals and plants into E. coli's well-known genetic structure. 90 00:09:41,070 --> 00:09:52,086 So cooperative are these bacteria that they willingly accept the foreign DNA and copy it as if it were their own. 91 00:09:52,086 --> 00:09:55,090 A revolution in medicine may be on the horizon. 92 00:09:55,090 --> 00:10:01,098 Already, gene splicing is being used to attack the human disease of diabetes. 93 00:10:01,098 --> 00:10:06,105 Scientists' long-time dream of genetic engineering is at hand. 94 00:10:06,105 --> 00:10:11,112 They are getting closer to the secrets of life. 95 00:10:15,118 --> 00:10:21,126 Since the discovery of DNA, biologists have been manipulating the very essence of life. 96 00:10:25,132 --> 00:10:30,139 Today, they can take DNA out of one cell and insert it into another. 97 00:10:30,139 --> 00:10:33,143 They can even mix the genes of different species. 98 00:10:33,143 --> 00:10:40,153 By transplanting animal genes into bacteria, they hope to find out how these genes work and are controlled. 99 00:10:45,160 --> 00:10:52,170 The process begins when a strain of bacteria is given an ample supply of food and gently shaken. 100 00:11:01,182 --> 00:11:07,191 In less than 24 hours, each bacterium can multiply 100 billion fold. 101 00:11:11,197 --> 00:11:19,208 After the bacteria are harvested, a detergent bursts open their cell walls and sticky DNA strands spill out. 102 00:11:21,211 --> 00:11:25,216 Most of the DNA clumps together in a disarray-tangle. 103 00:11:26,218 --> 00:11:32,226 But nearby are tiny loops of DNA called plasmids. 104 00:11:36,232 --> 00:11:40,237 They are the key to the new technology of gene splicing. 105 00:11:40,237 --> 00:11:44,243 They will accept any genes the biologists can stitch into them. 106 00:11:45,244 --> 00:11:50,251 A fast-spinning centrifuge separates the plasmids from the rest of the DNA. 107 00:11:54,257 --> 00:11:59,264 Under ultraviolet light, a fluorescent dye makes the plasmid band visible. 108 00:12:02,268 --> 00:12:06,274 Carefully, the precious plasmids are removed. 109 00:12:07,275 --> 00:12:10,279 Now come the most crucial steps. 110 00:12:10,279 --> 00:12:14,285 In this simulation, a special enzyme is added to the plasmids. 111 00:12:14,285 --> 00:12:20,293 By compare of microscopic scissors, it snips open their DNA molecules at specific points. 112 00:12:20,293 --> 00:12:25,300 Other snipped genes can now be added to the open plasmid loops. 113 00:12:27,303 --> 00:12:32,310 The best way to do this is to use a special enzyme. 114 00:12:32,310 --> 00:12:36,316 The new plasmid band is used to make the open plasmid loops. 115 00:12:36,316 --> 00:12:41,323 The foreign DNA joins the plasmids, creating a new DNA molecule. 116 00:12:41,323 --> 00:12:48,332 The resulting loops, called recombinant DNA, combine animal genes with bacterial genes. 117 00:12:48,332 --> 00:12:54,341 They will be reinserted into other bacteria, giving those bacteria new genes. 118 00:12:55,342 --> 00:13:01,351 When the bacteria multiply, their new blueprint is copied over and over. 119 00:13:03,354 --> 00:13:09,362 Thus, science can make life forms with new combinations of genes. 120 00:13:12,366 --> 00:13:18,375 Dr. William Rudder is chairman of the biochemistry department at the University of California, San Francisco. 121 00:13:18,375 --> 00:13:23,382 The possibilities for recombinant DNA technology are simply enormous. 122 00:13:24,383 --> 00:13:32,394 Not only are we going to revolutionize the understanding of the human genome and for genetics in general, 123 00:13:32,394 --> 00:13:37,401 but we will have profound effects on many aspects of biomedical science. 124 00:13:38,403 --> 00:13:43,410 Over 40 million people are affected by the genetic disease called diabetes. 125 00:13:43,410 --> 00:13:49,418 In the United States alone, more than a million people inject insulin each day in order to stay alive. 126 00:13:49,418 --> 00:13:53,424 This insulin comes from the pancreas gland of animals. 127 00:13:53,424 --> 00:13:58,431 It is in short supply worldwide and often produces undesirable side effects. 128 00:13:59,432 --> 00:14:06,442 My colleagues and I have been studying the expression of the insulin gene in the embryonic rat pancreas for several years. 129 00:14:06,442 --> 00:14:12,450 And one day I attended a faculty meeting at which Herbert Boyer and Howard Goodman were discussing their work on recombinant DNA. 130 00:14:12,450 --> 00:14:14,453 This excited me a great deal. 131 00:14:14,453 --> 00:14:18,459 And I cornered these two individuals after the meeting and said, 132 00:14:18,459 --> 00:14:22,464 Herb and Howard, we just must clone the insulin gene. 133 00:14:22,464 --> 00:14:27,471 What the scientists proposed to do would have seemed impossible ten years ago. 134 00:14:27,471 --> 00:14:31,477 Of the thousands of genes in each cell of the laboratory rat, 135 00:14:31,477 --> 00:14:36,484 they wanted to isolate the single gene that makes insulin in the rat's pancreas gland. 136 00:14:37,485 --> 00:14:46,498 Then they would transplant this gene into bacteria hoping to create a microbe with the insulin producing ability of a mammal. 137 00:14:54,509 --> 00:14:57,513 If they could make it work for the insulin gene, 138 00:14:57,513 --> 00:15:02,520 it might become possible to make dozens of important hormones and drugs. 139 00:15:06,526 --> 00:15:11,533 A group of scientists at the university began to collaborate on the experiments. 140 00:15:14,537 --> 00:15:17,541 So we obtained the insulin producing cells from several hundred rats 141 00:15:17,541 --> 00:15:21,547 and extracted from them the chemicals from which we could get the DNA. 142 00:15:24,551 --> 00:15:27,555 Axolorec took this material, inserted it into a plasmid, 143 00:15:27,555 --> 00:15:32,562 and placed the plasmid into a strain of bacteria that could only grow in the laboratory. 144 00:15:33,564 --> 00:15:38,571 These steps of the experiment were carried out under strict conditions of containment. 145 00:15:39,572 --> 00:15:45,581 Howard Goodman is professor of biochemistry at the University of California, San Francisco. 146 00:15:45,581 --> 00:15:50,588 We had been working on the cloning of rat insulin for about a year. 147 00:15:50,588 --> 00:15:54,593 We had many technical difficulties and we began to overcome them. 148 00:15:54,593 --> 00:15:57,597 But it wasn't until the moment I saw this film, 149 00:15:57,597 --> 00:16:00,602 which was the analysis of the gene that we had cloned 150 00:16:00,602 --> 00:16:04,607 that we really knew we had the rat insulin gene in the bacteria. 151 00:16:05,609 --> 00:16:09,614 The next step is to show that the genes which we have transplanted to the bacteria 152 00:16:09,614 --> 00:16:12,618 can actually work and produce insulin. 153 00:16:12,618 --> 00:16:16,624 We'll then try to insert human genes into bacteria instead of the rat genes. 154 00:16:16,624 --> 00:16:22,632 If we can get these genes to work, this would provide a virtually inexhaustible supply of human insulin, 155 00:16:22,632 --> 00:16:26,638 much better than animal insulin since it would have no undesirable side effects. 156 00:16:28,641 --> 00:16:34,649 Eventually, in a generation or so, we might be able to do something which is really fantastic. 157 00:16:34,649 --> 00:16:38,655 It might be possible to rejuvenate the defective cells of the diabetics 158 00:16:38,655 --> 00:16:43,662 so that they would produce insulin in a normal fashion, thus the disease would be cured. 159 00:16:47,667 --> 00:16:54,677 In the future, bacteria modified with recombinant DNA may be grown in industrial amounts. 160 00:16:58,683 --> 00:17:03,690 The bacteria could produce hormones like insulin and other important drugs. 161 00:17:03,690 --> 00:17:11,701 New fast-growing strains of bacteria or algae could be used in vast amounts as animal feed or fuel. 162 00:17:17,710 --> 00:17:21,715 A whole new technology will be needed to pick the desired bacteria. 163 00:17:27,724 --> 00:17:40,742 Automation will be used to inoculate, incubate and photograph bacteria. 164 00:17:49,754 --> 00:17:53,760 The system produces thousands of photographs under computer control. 165 00:17:53,760 --> 00:17:58,767 These could be used to select the most productive bacteria for industrial use. 166 00:18:01,771 --> 00:18:06,778 Breakthroughs in genetic engineering may open up a whole new realm of biology. 167 00:18:06,778 --> 00:18:13,788 Until recently, it has been very difficult to identify specific genes on animal chromosomes. 168 00:18:13,788 --> 00:18:20,798 But with new techniques of gene splicing, scientists have begun to map the uncharted terrain of the chromosome. 169 00:18:24,803 --> 00:18:31,813 Stanford University biologists have made a remarkable photograph of fruit fly chromosomes. 170 00:18:31,813 --> 00:18:41,827 While trying to locate a certain gene on one chromosome, they found to their surprise that the gene's DNA code was repeated dozens of times. 171 00:18:41,827 --> 00:18:47,836 To explain this important finding, the scientists came up with a new idea. 172 00:18:48,837 --> 00:18:56,848 Just as each letter of the alphabet is found in many different words, each gene copy may play a different role in the life process of the fly. 173 00:18:59,852 --> 00:19:09,867 Biologists are now busy testing this idea. It could be the key to the miracle of growth, helping explain how a human being develops from a fertilized egg. 174 00:19:10,868 --> 00:19:16,876 The new molecular biology is leading to cures for genetic diseases. 175 00:19:16,876 --> 00:19:21,883 It may enable us to engineer our own genes and influence our destiny. 176 00:19:21,883 --> 00:19:27,892 It might even lead to complete knowledge of the secret of life. 177 00:19:27,892 --> 00:19:35,903 But is it possible to explain life in terms of chemicals and molecules, or to explain life in terms of life? 178 00:19:35,903 --> 00:19:42,913 Or are there profound mysteries beyond the gene? 179 00:19:46,918 --> 00:19:55,931 While raising hopes of great advances in medicine and biology, recombinant DNA research has also created a major controversy. 180 00:19:55,931 --> 00:19:59,937 Tinkering with the stuff of life is not without its risks. 181 00:20:00,938 --> 00:20:06,946 Some people are afraid that a bit of DNA spliced into a harmless bacterium could create a deadly germ. 182 00:20:06,946 --> 00:20:12,955 Others fear that mixing genes from different species could have unpredictable effects on evolution. 183 00:20:12,955 --> 00:20:18,963 Government agencies have enacted strict controls for recombinant DNA research. 184 00:20:18,963 --> 00:20:24,972 Most scientists say that if these guidelines are followed, genetic engineering is not dangerous. 185 00:20:24,972 --> 00:20:32,983 With today's technology, we can only add a few foreign genes to bacteria. 186 00:20:32,983 --> 00:20:39,993 But a hundred years from now, we may be able to mold genetic structure as freely as a sculptor shapes clay. 187 00:20:39,993 --> 00:20:47,002 The question is, will we be ready for the power to change life? 188 00:20:48,004 --> 00:21:03,025 Coming up next in search of continues with a probe into the eerie possibility of artificially creating child prodigies. 189 00:21:03,025 --> 00:21:10,035 Then on FBI, the untold stories, a woman kills the state prosecutor who put her husband behind bars, 190 00:21:10,035 --> 00:21:13,039 but was something more than love involved. 191 00:21:13,039 --> 00:21:21,050 And later tonight, history's greatest blunders continues with the sinking of the Titanic and the Andrea Doria 192 00:21:21,050 --> 00:21:27,059 at 9 Eastern 10 Pacific here on the History Channel, where the past comes alive.