1 00:00:16,950 --> 00:00:20,550 I've been fascinated by plants for my entire life. 2 00:00:20,550 --> 00:00:23,670 They are nature's most innovative creation. 3 00:00:25,550 --> 00:00:28,550 And yet, what is most surprising 4 00:00:28,550 --> 00:00:30,830 is that almost all the plants that we grow 5 00:00:30,830 --> 00:00:33,550 have been altered in some way by people. 6 00:00:35,550 --> 00:00:41,830 For 10,000 years, humans have created new plant varieties for food. 7 00:00:43,150 --> 00:00:45,430 We used trial and error. 8 00:00:48,110 --> 00:00:50,710 Then, 150 years ago, 9 00:00:50,710 --> 00:00:52,590 a new era began. 10 00:00:55,630 --> 00:00:59,070 Pioneer botanists used science to breed plants, 11 00:00:59,070 --> 00:01:04,110 and set out to discover how plants passed unique qualities 12 00:01:04,110 --> 00:01:06,630 from one generation to the next. 13 00:01:09,910 --> 00:01:15,110 Botanists began to discover how plants create their astonishing variety. 14 00:01:17,750 --> 00:01:21,630 They puzzled over the colour of snapdragon petals... 15 00:01:21,630 --> 00:01:25,670 and the strange patterns in wild maize. 16 00:01:25,670 --> 00:01:29,750 Some gave their lives to protect valuable seeds. 17 00:01:31,190 --> 00:01:36,070 And together they unlocked the secrets of plants for the benefit of us all. 18 00:01:39,670 --> 00:01:42,950 The long quest to understand the world of plants 19 00:01:42,950 --> 00:01:47,990 would lead botanists to develop a new tool - plant genetics. 20 00:01:47,990 --> 00:01:54,950 Today, botany is at the forefront of attempts to rescue a rising world population from starvation 21 00:01:54,950 --> 00:01:59,430 through the production of new and improved varieties of our staple crops. 22 00:02:14,390 --> 00:02:19,270 Plants really are the most incredible living things on earth, 23 00:02:19,270 --> 00:02:24,510 sometimes simple, sometimes complex, but always beautiful. 24 00:02:33,350 --> 00:02:36,790 And what really blows me away is the sheer variety. 25 00:02:36,790 --> 00:02:39,630 Just as you think you've seen everything, 26 00:02:39,630 --> 00:02:41,390 you look at a new flower 27 00:02:41,390 --> 00:02:44,070 and you see something which you've never seen before. 28 00:02:48,870 --> 00:02:52,310 The variety works on so many different levels, 29 00:02:52,310 --> 00:02:55,270 so you have trees, you have climbers, you have herbs, 30 00:02:55,270 --> 00:03:00,150 and then within the flowers you've got the diversity of colours, the diversity of shapes, 31 00:03:00,150 --> 00:03:03,070 and then you find varieties on a theme, 32 00:03:03,070 --> 00:03:07,070 so you find members of the daisy family, you find different scents, 33 00:03:07,070 --> 00:03:11,310 so you have a plant there that smells like it's a tin of cherry-pie filling... 34 00:03:11,310 --> 00:03:18,070 and all of this variety is there to do the same thing, which is to produce more plants. 35 00:03:18,070 --> 00:03:22,910 And even within a group of plants that are clearly the same species, 36 00:03:22,910 --> 00:03:25,510 you get a variation of height and of colour. 37 00:03:25,510 --> 00:03:28,070 The diversity's endlessly wonderful. 38 00:03:32,110 --> 00:03:36,870 How does this complexity of form and function come about? 39 00:03:36,870 --> 00:03:38,870 It's always fascinated me, 40 00:03:38,870 --> 00:03:43,990 because variety among edible plants has huge implications. 41 00:03:43,990 --> 00:03:46,390 It's the key to producing more food. 42 00:03:46,390 --> 00:03:49,630 To botanists in the 19th century, 43 00:03:49,630 --> 00:03:55,270 how plants generated variation was the greatest puzzle in science. 44 00:03:57,830 --> 00:04:03,030 150 years ago, even the great Charles Darwin described us as 45 00:04:03,030 --> 00:04:08,390 profoundly ignorant of the mechanism whereby this variety was generated. 46 00:04:12,310 --> 00:04:16,910 As botanists began to unveil the mechanism behind variation, 47 00:04:16,910 --> 00:04:20,310 they laid the foundations of plant genetics... 48 00:04:21,950 --> 00:04:25,510 ..genetics which showed botanists how plant characteristics 49 00:04:25,510 --> 00:04:29,430 are passed on from one generation to the next. 50 00:04:30,990 --> 00:04:34,670 It would give them the power to tamper with the laws of nature 51 00:04:34,670 --> 00:04:37,390 and the means to feed the world. 52 00:04:39,270 --> 00:04:46,910 And yet the story of plant genetics begins with something we see around us every day... 53 00:04:51,590 --> 00:04:55,510 ..a concept so familiar, it's easy to take for granted... 54 00:04:59,470 --> 00:05:01,470 ..inheritance. 55 00:05:05,670 --> 00:05:10,150 If you look at any population of plants or animals or people, 56 00:05:10,150 --> 00:05:14,630 you notice that each individual is different from the next. 57 00:05:14,630 --> 00:05:20,230 Each is a unique combination of the characteristics inherited from their parents. 58 00:05:26,390 --> 00:05:31,390 But how do these characteristics get passed down from generation to generation? 59 00:05:31,390 --> 00:05:37,710 This is a question that has intrigued the new wave of biologists since Darwin. 60 00:05:42,590 --> 00:05:50,590 The first pieces of the inheritance puzzle will be put together far away in the Czech Republic. 61 00:05:53,830 --> 00:06:01,070 And the evidence is buried in an obscure scientific paper, published in 1866. 62 00:06:02,710 --> 00:06:07,430 The first thing you notice about this original copy is it's not in English, it's in German. 63 00:06:07,430 --> 00:06:11,950 Secondly, it's written by a monk, and thirdly... 64 00:06:13,430 --> 00:06:14,790 ..it's about peas. 65 00:06:17,870 --> 00:06:21,350 Gregor Mendel had been growing varieties of pea plant 66 00:06:21,350 --> 00:06:23,870 that had different characteristics, 67 00:06:23,870 --> 00:06:28,990 like whether the peas were wrinkled or smooth, yellow or green, 68 00:06:28,990 --> 00:06:31,590 whether the stems were tall or short... 69 00:06:31,590 --> 00:06:35,110 Plant breeders had done that kind of thing many times before. 70 00:06:35,110 --> 00:06:41,630 What was extraordinary about Mendel was he repeated the experiment again and again and again. 71 00:06:41,630 --> 00:06:48,590 And, even more critically, he wrote down the numbers of each kind of plant that he got in each generation. 72 00:06:48,590 --> 00:06:51,830 Mendel treats plant breeding as a science. 73 00:06:54,190 --> 00:06:58,430 And he spots something very odd in the numbers he's written down. 74 00:06:58,430 --> 00:07:04,030 The ratio of tall plants to short, or wrinkled to smooth, 75 00:07:04,030 --> 00:07:06,070 is always the same. 76 00:07:08,790 --> 00:07:11,590 Nobody had ever noticed this before. 77 00:07:14,150 --> 00:07:19,190 These patterns hold vital clues to understanding inheritance. 78 00:07:20,830 --> 00:07:26,630 But for 35 years, nobody in the scientific community understands its significance. 79 00:07:28,670 --> 00:07:35,190 In 1884, Mendel dies and his work disappears into obscurity. 80 00:07:39,070 --> 00:07:42,470 That is, until the turn of the 20th century, 81 00:07:42,470 --> 00:07:45,950 when Mendel would gain his greatest champion... 82 00:07:48,110 --> 00:07:49,670 ..William Bateson. 83 00:07:54,030 --> 00:07:56,750 Bateson's a Cambridge University zoologist. 84 00:07:56,750 --> 00:08:01,310 Plants fascinate him, but he's more used to working with animals. 85 00:08:03,590 --> 00:08:08,230 He wants to see if he can find the same inheritance patterns in animals 86 00:08:08,230 --> 00:08:10,670 as Mendel got with his peas. 87 00:08:14,670 --> 00:08:17,830 This is William Bateson's makeshift laboratory. 88 00:08:17,830 --> 00:08:21,670 For years, he runs a series of experiments wherever he can, 89 00:08:21,670 --> 00:08:24,830 in his own garden, even in a disused church. 90 00:08:24,830 --> 00:08:30,590 This is because the authorities at Cambridge University believe his work on understanding inheritance 91 00:08:30,590 --> 00:08:33,670 is incomprehensible and therefore futile. 92 00:08:33,670 --> 00:08:36,230 So his funding is pitiful. 93 00:08:38,030 --> 00:08:43,630 Bateson's career at Cambridge had started as manager of the college kitchens, 94 00:08:43,630 --> 00:08:47,830 hardly as promising sign of future success in science. 95 00:08:49,030 --> 00:08:52,390 But if you have to say one thing about Bateson, he is tenacious. 96 00:08:52,390 --> 00:08:59,070 He has an unshakeable belief that he is on the verge of discovering something of huge importance. 97 00:09:02,070 --> 00:09:06,990 Wherever Bateson goes, the whiff of animal droppings soon follows. 98 00:09:06,990 --> 00:09:11,190 Ever since a colleague gave him a copy of Mendel's paper, 99 00:09:11,190 --> 00:09:14,430 Bateson's been hooked on inheritance. 100 00:09:17,870 --> 00:09:22,590 He wants to know if the patterns of inheritance Mendel got in peas 101 00:09:22,590 --> 00:09:28,390 are the result of a set of universal laws across the whole of the living world. 102 00:09:28,390 --> 00:09:30,510 And that includes plants. 103 00:09:32,590 --> 00:09:37,470 His plan is to crossbreed all kinds of different animals 104 00:09:37,470 --> 00:09:41,550 and to do the same for plants, a hugely laborious task. 105 00:09:43,110 --> 00:09:46,550 Without a team of helpers and no budget to pay for one, 106 00:09:46,550 --> 00:09:48,550 it will be impossible. 107 00:09:50,990 --> 00:09:56,430 But Bateson sees an opportunity to tap into an underused workforce on his doorstep... 108 00:09:56,430 --> 00:10:01,070 the students of Cambridge's Newnham College. 109 00:10:02,190 --> 00:10:04,430 They are the perfect workforce, 110 00:10:04,430 --> 00:10:09,550 fiercely intelligent, unemployed and they're all female. 111 00:10:09,550 --> 00:10:13,350 They become known as Bateson's ladies. 112 00:10:14,590 --> 00:10:16,430 Bateson and the ladies get cracking, 113 00:10:16,430 --> 00:10:20,910 and they start by looking for patterns of inheritance in chickens. 114 00:10:24,630 --> 00:10:27,270 So this is the sort of experiment they do. 115 00:10:27,270 --> 00:10:31,670 They cross a black cockerel and a black hen and get a brood of chicks. 116 00:10:32,830 --> 00:10:38,230 But what intrigues them, surprises them, is that not all of the chicks are black. 117 00:10:38,230 --> 00:10:40,590 Some of them are white. 118 00:10:43,470 --> 00:10:48,030 And the more times they repeat the experiment, the stranger it gets. 119 00:10:48,030 --> 00:10:54,390 The ratio of black to white is always 3-1. 120 00:10:54,390 --> 00:10:56,830 Every time. 121 00:10:59,910 --> 00:11:03,190 The parents must have passed down some instruction 122 00:11:03,190 --> 00:11:06,710 to cause this chick to be white and these ones to be black. 123 00:11:09,070 --> 00:11:13,710 Those elusive instructions we now know as genes. 124 00:11:15,390 --> 00:11:20,910 Genes are too small to be seen with the technology Bateson and his ladies had in their day. 125 00:11:22,470 --> 00:11:25,270 Genetics was a different kind of science. 126 00:11:27,190 --> 00:11:31,430 Bateson and his ladies used crossbreeding experiments and logic 127 00:11:31,430 --> 00:11:35,510 to make sense of the three-black-to-one-white ratio in their chickens. 128 00:11:40,070 --> 00:11:43,270 So, how can you get this 3-1 ratio? 129 00:11:43,270 --> 00:11:46,710 Well, we know that both of the parents contain the information for black feathers 130 00:11:46,710 --> 00:11:48,830 because they are both black. 131 00:11:48,830 --> 00:11:54,150 But we also know that somewhere hidden inside them there is information for white feathers, 132 00:11:54,150 --> 00:11:58,270 because between them they can produce a white bird. 133 00:11:58,270 --> 00:12:03,990 So there must be at least two sets of information in each parent for feather colour, 134 00:12:03,990 --> 00:12:06,270 one black and one white. 135 00:12:07,550 --> 00:12:12,430 So Bateson tries to work out how those two pieces of information 136 00:12:12,430 --> 00:12:16,630 could lead to the 3-1 ratio, and this is how he did it. 137 00:12:18,110 --> 00:12:21,950 Imagine that a chick gets information for black feathers from its father 138 00:12:21,950 --> 00:12:24,350 and information for black feathers from its mother. 139 00:12:24,350 --> 00:12:28,230 Or it could inherit black from dad and white from mum, 140 00:12:28,230 --> 00:12:31,990 or white from dad and black from mum. 141 00:12:31,990 --> 00:12:37,310 Or, finally, it could get information for white feathers from both of them. 142 00:12:39,070 --> 00:12:43,350 Bateson and his team observe that breeding from a pair of black chickens 143 00:12:43,350 --> 00:12:46,910 always produces three black chicks for every white chick. 144 00:12:47,950 --> 00:12:53,510 To explain that observation, he has to make one final logical assumption. 145 00:12:55,350 --> 00:13:01,110 Bateson deduces that the information for black feathers overrides the information for white, 146 00:13:01,110 --> 00:13:05,070 so in three of the chicks you get black feathers. 147 00:13:05,070 --> 00:13:08,670 One...two...three. 148 00:13:09,710 --> 00:13:14,190 Only when the chick gets information for white feathers from both of its parents 149 00:13:14,190 --> 00:13:19,070 and no instructions for black feathers do you get a white chick. 150 00:13:19,070 --> 00:13:24,870 And bingo! You have your 3-1, three black, one white ratio. 151 00:13:26,150 --> 00:13:31,550 If Bateson's explanation works for chickens, what about other animals? 152 00:13:33,870 --> 00:13:35,910 And why stop there? 153 00:13:35,910 --> 00:13:40,910 He knows that it holds true for peas, but what about other plants? 154 00:13:40,910 --> 00:13:46,110 Perhaps every living thing is governed by the same laws of inheritance. 155 00:13:46,110 --> 00:13:50,510 To find out, he'll need to look beyond his chickens. 156 00:13:56,710 --> 00:14:04,390 Bateson and his ladies breed pigeons, goats, guinea pigs, rabbits, mice... 157 00:14:05,590 --> 00:14:10,350 Wherever they look, they find the same inheritance patterns they found with their chickens, 158 00:14:10,350 --> 00:14:14,350 the same that Mendel found with his peas. 159 00:14:17,830 --> 00:14:22,750 Everywhere, in every species, the patterns are confirmed. 160 00:14:22,750 --> 00:14:27,510 And Bateson is blown away because he believes he has found the key 161 00:14:27,510 --> 00:14:35,470 to the mechanism by which all living creatures inherit the features that make them them. 162 00:14:35,470 --> 00:14:39,430 And the only way the ratios can be explained 163 00:14:39,430 --> 00:14:44,630 is if those features are passed down from generation to generation 164 00:14:44,630 --> 00:14:47,950 in discrete units of inheritance. 165 00:14:49,870 --> 00:14:52,230 A new science is born. 166 00:14:52,230 --> 00:14:55,710 Bateson gives it the name by which we now know it... 167 00:14:55,710 --> 00:14:57,430 genetics. 168 00:14:59,710 --> 00:15:03,630 In a matter of years, Bateson has turned from marginal eccentric 169 00:15:03,630 --> 00:15:06,550 into international scientific superstar. 170 00:15:09,350 --> 00:15:14,630 He has proved that the strange numbers Mendel first saw in peas 171 00:15:14,630 --> 00:15:19,110 are the result of a set of universal genetic laws. 172 00:15:25,030 --> 00:15:28,870 These laws explain how animal and plant characteristics 173 00:15:28,870 --> 00:15:31,910 are inherited in past generations, 174 00:15:31,910 --> 00:15:38,830 and the same laws can now be used to predict how they will be inherited in future generations of plants. 175 00:15:49,150 --> 00:15:52,790 But in 1903, Bateson hits a problem. 176 00:15:55,350 --> 00:15:58,510 There's a plant lurking at the back of his laboratory 177 00:15:58,510 --> 00:16:01,390 that doesn't seem to be playing according to the rules. 178 00:16:01,390 --> 00:16:05,390 It seems to defy everything Bateson has learned about genetics. 179 00:16:05,390 --> 00:16:07,870 The plant is snapdragon 180 00:16:07,870 --> 00:16:10,950 and the problem is the colour of its flowers. 181 00:16:20,510 --> 00:16:22,990 From one generation to the next, 182 00:16:22,990 --> 00:16:27,430 the inheritance of colours seems utterly unpredictable. 183 00:16:27,430 --> 00:16:30,590 New colours seem to come out of nowhere. 184 00:16:30,590 --> 00:16:32,590 Yellow... 185 00:16:32,590 --> 00:16:34,270 crimson... 186 00:16:35,390 --> 00:16:36,630 ..magenta. 187 00:16:38,550 --> 00:16:44,310 Bateson has to question if the laws of genetics have reached their limit with snapdragons. 188 00:16:45,670 --> 00:16:50,870 So he puts one of the brightest geneticists in his female team on the case... 189 00:16:52,390 --> 00:16:54,230 ..Muriel Wheldale. 190 00:16:55,390 --> 00:17:00,750 Wheldale has an uncommon gift for making sense of complex patterns. 191 00:17:02,150 --> 00:17:04,510 And she loves snapdragons. 192 00:17:07,230 --> 00:17:12,270 Wheldale sets about her task armed with state-of-the-art genetic technology... 193 00:17:12,270 --> 00:17:16,510 pencil, paper and lots of patience. 194 00:17:18,350 --> 00:17:22,070 Wheldale has to do crossbreeding experiments just like Mendel. 195 00:17:23,510 --> 00:17:26,670 Wheldale takes the pollen from one type of flower 196 00:17:26,670 --> 00:17:31,870 and crossbreeds it with another plant by dabbing the pollen on its flowers... 197 00:17:33,070 --> 00:17:35,470 ..and grows new plants from the seed. 198 00:17:39,070 --> 00:17:42,430 Then she has to count the number of flowers of each colour that come up. 199 00:17:44,270 --> 00:17:46,590 Then repeat...hundreds of times 200 00:17:46,590 --> 00:17:49,110 with hundreds of plants. 201 00:17:51,710 --> 00:17:54,710 It looks mind-numbing and it is mind-numbing! 202 00:17:54,710 --> 00:17:59,310 And this period of genetic research was called "the bean-counting period". 203 00:17:59,310 --> 00:18:03,310 The trick was to remain focused on solving the problem. 204 00:18:08,350 --> 00:18:13,510 For four years Wheldale sows and grows and counts... 205 00:18:13,510 --> 00:18:17,270 until finally she makes a breakthrough. 206 00:18:18,670 --> 00:18:25,270 Wheldale works out that there are several genes that influence the colour of snapdragon flowers. 207 00:18:26,750 --> 00:18:32,030 Every possible combination of those genes generates its own unique colour. 208 00:18:34,350 --> 00:18:36,950 It's a simple secret code, 209 00:18:36,950 --> 00:18:39,710 and Wheldale has cracked it. 210 00:18:44,430 --> 00:18:48,510 Now she can predict the inheritance of these colours... 211 00:18:50,310 --> 00:18:52,790 ..just like anything else in nature. 212 00:18:56,470 --> 00:19:00,990 The colours of snapdragon flowers may seem trivial and whimsical, 213 00:19:00,990 --> 00:19:05,670 but they reveal something fundamental to all of life on earth. 214 00:19:05,670 --> 00:19:08,510 And the truth is perhaps shocking, 215 00:19:08,510 --> 00:19:16,150 that the amazing biological diversity that we see around us does not require a supernatural explanation. 216 00:19:16,150 --> 00:19:22,110 It is the result of genes working together like the components of a beautiful machine. 217 00:19:26,590 --> 00:19:31,950 Bateson showed that Mendel's laws of inheritance were true. 218 00:19:31,950 --> 00:19:38,710 Wheldale proved that genetics could predict the inheritance of even the most complex features. 219 00:19:44,150 --> 00:19:49,670 By 1913, botanists see genes as a car-assembly line. 220 00:19:49,670 --> 00:19:56,390 Genes are the components of machines, ready to be assembled and exploited by crossbreeding. 221 00:20:10,030 --> 00:20:14,590 Out of the First World War comes a new generation of botanists 222 00:20:14,590 --> 00:20:17,990 who can see that the future of genetics will change the world. 223 00:20:21,590 --> 00:20:26,270 They want to put genetics to practical use. 224 00:20:35,350 --> 00:20:41,270 A 29-year-old Ukrainian called Nikolai Vavilov is lucky to be alive. 225 00:20:43,110 --> 00:20:48,070 He has narrowly avoided falling to his death in the mountains of Central Asia. 226 00:20:52,670 --> 00:20:55,230 As far as Vavilov's concerned, 227 00:20:55,230 --> 00:20:58,990 what's at stake is well worth the risk. 228 00:21:06,030 --> 00:21:10,950 He's the first botanist to understand the true potential of genetics 229 00:21:10,950 --> 00:21:13,230 to revolutionise agriculture. 230 00:21:20,230 --> 00:21:22,670 Nikolai Vavilov is a plant breeder. 231 00:21:22,670 --> 00:21:27,670 He is just back from an expedition collecting plants with valuable attributes. 232 00:21:27,670 --> 00:21:31,910 He wants to cross them to create a new generation of crops. 233 00:21:31,910 --> 00:21:34,870 This is more than a passion for Vavilov. 234 00:21:34,870 --> 00:21:37,310 The fate of the nation is at stake 235 00:21:37,310 --> 00:21:41,830 and he believes that plant genetics can save the Soviet Union. 236 00:21:46,030 --> 00:21:50,950 The Russian Revolution has left agriculture in chaos. 237 00:21:50,950 --> 00:21:54,790 The new Soviet Union is unable to feed itself. 238 00:21:57,790 --> 00:22:01,630 Nikolai Vavilov learned genetics in Europe. 239 00:22:03,470 --> 00:22:07,990 Many evenings spent deep in discussion with William Bateson in Cambridge 240 00:22:07,990 --> 00:22:10,470 have sparked Vavilov's imagination. 241 00:22:12,310 --> 00:22:16,030 Vavilov's plan is to crossbreed the plants he collects 242 00:22:16,030 --> 00:22:19,630 to create new combinations of characteristics, 243 00:22:19,630 --> 00:22:21,990 super crops for the Soviet Union. 244 00:22:24,070 --> 00:22:28,830 Vavilov thinks that he can create a revolutionary set of new crops, 245 00:22:28,830 --> 00:22:31,510 assembling them using the best components, 246 00:22:31,510 --> 00:22:33,870 like cars on a production line. 247 00:22:33,870 --> 00:22:37,390 And the expedition from which he has just returned is the start. 248 00:22:37,390 --> 00:22:42,030 Imagine being able to create a fruit tree that can fight every disease 249 00:22:42,030 --> 00:22:46,190 or a super wheat that combines the yield of wheat from the plains 250 00:22:46,190 --> 00:22:48,910 and the cold tolerance of wheat from the mountains. 251 00:22:53,630 --> 00:22:59,350 Vavilov realises that plants with valuable properties will not all be found in Russia. 252 00:23:11,430 --> 00:23:14,590 To crossbreed his new generation of crops, 253 00:23:14,590 --> 00:23:19,470 Vavilov will need to combine varieties collected from right across the globe. 254 00:23:23,190 --> 00:23:29,510 Little by little, he gathers the seeds of every plant he finds in a central vault. 255 00:23:32,910 --> 00:23:36,750 He's the pioneer of worldwide seed banks. 256 00:23:40,790 --> 00:23:44,110 A seed is a survival capsule. 257 00:23:44,110 --> 00:23:50,510 It contains not only the embryonic plant, but also a food supply and a tough outer coat. 258 00:23:50,510 --> 00:23:54,430 It could almost have been designed for the storage of genes. 259 00:23:55,910 --> 00:24:01,030 Vavilov was a pioneer in the movement to use seeds 260 00:24:01,030 --> 00:24:06,190 as a way of preserving our biological inheritance 261 00:24:06,190 --> 00:24:08,390 for generations to come. 262 00:24:08,390 --> 00:24:13,030 And there is now a worldwide movement of seed banks 263 00:24:13,030 --> 00:24:17,150 conserving not only our varieties that we have already, 264 00:24:17,150 --> 00:24:22,390 but also the wild relatives of the crops that we shall need in the future 265 00:24:22,390 --> 00:24:28,110 to make plants to produce more and more food in different conditions. 266 00:24:33,990 --> 00:24:39,830 Vavilov's worldwide seed bank is the first step in his bold strategy 267 00:24:39,830 --> 00:24:42,550 to create super crops for the USSR. 268 00:24:46,150 --> 00:24:48,950 Lenin buys into Vavilov's vision 269 00:24:48,950 --> 00:24:54,110 and puts him in charge of the most influential agricultural bodies in the Soviet Union. 270 00:25:00,750 --> 00:25:06,070 Vavilov is to be responsible for a new scientific approach to breeding crops. 271 00:25:11,270 --> 00:25:15,750 Until now it has taken centuries to breed plants with useful features, 272 00:25:15,750 --> 00:25:20,350 but, armed with the new understanding of genetics, Vavilov can work much faster. 273 00:25:24,910 --> 00:25:29,790 But even by Vavilov's most optimistic estimates, the work will take years. 274 00:25:30,910 --> 00:25:33,950 He was often heard to say, "Life is short. We must hurry." 275 00:25:34,790 --> 00:25:37,390 He couldn't possibly have known how right he was. 276 00:25:47,870 --> 00:25:53,470 By 1929, the USSR is under the control of Joseph Stalin. 277 00:25:55,670 --> 00:25:58,230 Stalin doesn't understand science. 278 00:25:58,230 --> 00:26:02,390 He has no patience for the likes of Vavilov. 279 00:26:04,030 --> 00:26:10,710 He insists the USSR needs methods to increase crop yields that make a difference tomorrow, 280 00:26:10,710 --> 00:26:13,590 not in ten years' time. 281 00:26:16,710 --> 00:26:20,270 Stalin's men say genes do not exist. 282 00:26:20,270 --> 00:26:24,430 Only the environment in which a plant grows up is important. 283 00:26:25,390 --> 00:26:28,430 It fits Marxist ideology beautifully. 284 00:26:28,430 --> 00:26:31,590 Breeding and birthright count for nothing. 285 00:26:31,590 --> 00:26:36,590 Genetics, they say, is bourgeois Western propaganda, 286 00:26:36,590 --> 00:26:43,710 and slowly Soviet geneticists realise that their science is a political liability. 287 00:26:58,150 --> 00:27:00,510 These are dangerous times. 288 00:27:01,550 --> 00:27:08,310 At the age of 45, Vavilov has invested decades in his great genetic project. 289 00:27:10,110 --> 00:27:11,790 Then disaster strikes. 290 00:27:11,790 --> 00:27:15,830 A series of catastrophic harvests hits the USSR. 291 00:27:15,830 --> 00:27:18,590 Stalin is looking for a scapegoat. 292 00:27:18,590 --> 00:27:23,950 Vavilov runs several agricultural institutions. He's the perfect target. 293 00:27:29,590 --> 00:27:33,550 A summer evening in the Carpathian Mountains of Ukraine. 294 00:27:35,070 --> 00:27:37,390 Vavilov collects plants. 295 00:27:38,510 --> 00:27:42,030 On this occasion, though, he is not alone. 296 00:27:56,110 --> 00:27:59,790 Four men disguised as local bureaucrats 297 00:27:59,790 --> 00:28:02,430 have searched for him all day. 298 00:28:04,990 --> 00:28:07,510 They are Stalin's secret police. 299 00:28:14,870 --> 00:28:18,390 These are Nikolai Vavilov's last moments of freedom. 300 00:28:26,870 --> 00:28:29,950 On 26 January 1943, 301 00:28:29,950 --> 00:28:32,950 Vavilov dies on the floor of a prison cell. 302 00:28:32,950 --> 00:28:36,990 The man who has devoted his life to feeding the Soviet Union 303 00:28:37,230 --> 00:28:40,470 succumbs finally to, of all things, starvation, 304 00:28:40,470 --> 00:28:44,390 and genetics in the Soviet Union is put back decades. 305 00:29:03,950 --> 00:29:10,070 World events now threaten to wipe out Vavilov's global work to develop genetics. 306 00:29:17,430 --> 00:29:19,950 The Second World War... 307 00:29:19,950 --> 00:29:22,710 it's the siege of Leningrad. 308 00:29:26,190 --> 00:29:29,430 12 Russian scientists who have worked with Vavilov 309 00:29:29,430 --> 00:29:33,470 have been trapped in an underground vault for the last three months. 310 00:29:36,750 --> 00:29:40,110 German artillery is pummelling the street outside, 311 00:29:40,110 --> 00:29:42,550 yet the scientists trapped inside the vault 312 00:29:42,550 --> 00:29:46,950 believe they are protecting the Soviet Union's greatest treasure. 313 00:29:50,630 --> 00:29:53,550 They are guarding Vavilov's seed bank, 314 00:29:53,550 --> 00:29:57,750 a vast collection of seeds from around the world, 315 00:29:57,750 --> 00:30:03,110 brought together to crossbreed crops for the future of all humankind. 316 00:30:10,430 --> 00:30:16,590 If the war destroys this collection, his life's work will have been in vain. 317 00:30:21,950 --> 00:30:27,670 It's almost impossible to imagine what it must have been like for those scientists trapped in that basement, 318 00:30:27,670 --> 00:30:33,110 because not only was there a battle raging above them with the enemy trying to kill them, 319 00:30:33,110 --> 00:30:38,390 but they were faced with the horrendous dilemma that they had no food. 320 00:30:38,390 --> 00:30:40,990 They were desperately hungry, 321 00:30:40,990 --> 00:30:44,310 yet they were surrounded by edible seeds... 322 00:30:44,310 --> 00:30:46,870 which they did not touch. 323 00:30:46,870 --> 00:30:49,870 The seed bank remained intact. 324 00:30:49,870 --> 00:30:56,070 And these scientists sacrificed themselves to preserve a genetic resource 325 00:30:56,070 --> 00:30:59,590 that we can all benefit from in future years. 326 00:31:14,030 --> 00:31:19,670 Mendel, Bateson and Wheldale first unveiled the universal laws of genetics 327 00:31:19,670 --> 00:31:22,910 that govern all plant characteristics. 328 00:31:28,310 --> 00:31:31,670 Vavilov tried to put those laws to use, 329 00:31:31,670 --> 00:31:35,190 to combine the properties of plants from around the globe. 330 00:31:36,790 --> 00:31:40,590 He thought he would trigger a revolution in agriculture. 331 00:31:44,990 --> 00:31:49,310 But Vavilov was stopped before he could see his dream realised. 332 00:31:57,430 --> 00:32:02,350 The global revolution in food production would fall to someone else. 333 00:32:13,590 --> 00:32:16,070 One year after Vavilov's death, 334 00:32:16,070 --> 00:32:19,110 an American plant breeder called Norman Borlaug 335 00:32:19,110 --> 00:32:24,310 is pacing his fields in a remote research station near Chapingo in Mexico. 336 00:32:30,790 --> 00:32:33,470 Borlaug is an ex-championship wrestler 337 00:32:33,470 --> 00:32:38,670 who grew up during the disastrous crop failures of the Midwest Dust Bowl. 338 00:32:38,670 --> 00:32:44,430 Maybe it was this that fuelled his determination to make agriculture work. 339 00:32:45,670 --> 00:32:48,470 Now he is a promising young plant breeder, 340 00:32:48,470 --> 00:32:53,150 specialising in making plants defend themselves against disease. 341 00:32:53,150 --> 00:32:55,590 And he's brought his knowledge to Mexico. 342 00:33:02,230 --> 00:33:07,910 Poor soils and fungal disease have held back farming in Mexico for generations. 343 00:33:10,430 --> 00:33:12,870 Borlaug is no lab geneticist, 344 00:33:12,870 --> 00:33:15,950 he's a hands-in-the-soil agriculturalist. 345 00:33:17,710 --> 00:33:21,790 But the advances in plant genetics by Bateson, Vavilov and others 346 00:33:21,790 --> 00:33:28,190 have given him an understanding of how to combine useful characteristics through crossbreeding. 347 00:33:30,270 --> 00:33:34,670 Borlaug has managed to crossbreed different varieties of wheat 348 00:33:34,670 --> 00:33:36,990 to increase disease resistance. 349 00:33:38,750 --> 00:33:44,590 But his most robust variety doesn't behave quite as he expects. 350 00:33:46,950 --> 00:33:51,230 Borlaug's plants grow too successfully. 351 00:33:51,230 --> 00:33:55,710 The heads are beautiful, plump, full of nutrition, 352 00:33:55,710 --> 00:33:58,990 but the stems are growing like crazy too, 353 00:33:58,990 --> 00:34:03,590 and they're too tall to support the heavy seed heads. 354 00:34:03,590 --> 00:34:07,390 So in the slightest gust of wind, they fall over. 355 00:34:07,390 --> 00:34:10,750 The seeds hit the ground, they rot, 356 00:34:10,750 --> 00:34:16,230 and that's a waste of time, effort and food. 357 00:34:20,350 --> 00:34:24,830 The solution to Borlaug's falling wheat comes out of the Second World War. 358 00:34:26,590 --> 00:34:29,150 Japan is defeated by the Allies. 359 00:34:29,150 --> 00:34:32,430 American troops spread across the country. 360 00:34:34,710 --> 00:34:39,150 The occupied territory is a new resource to be exploited. 361 00:34:44,750 --> 00:34:46,670 Like Vavilov before them, 362 00:34:46,670 --> 00:34:52,190 the Americans know that foreign lands hold new plants with unfamiliar properties. 363 00:34:57,630 --> 00:34:59,910 In a corner of Northeast Japan, 364 00:34:59,910 --> 00:35:06,910 American botanists stumble across a strain of wheat that seems to have adapted to the local climate. 365 00:35:09,430 --> 00:35:13,750 The discovery of this strain changes Borlaug's fortunes, 366 00:35:13,750 --> 00:35:17,390 and the fortunes of world food production. 367 00:35:18,710 --> 00:35:22,190 The strain is later named Norin 10. 368 00:35:26,950 --> 00:35:30,190 I'm guessing you haven't heard of Norin 10, 369 00:35:30,190 --> 00:35:35,510 and compared to the other wheat growing around the world at the time of its discovery, 370 00:35:35,510 --> 00:35:40,270 it wasn't much different, apart from the fact that it grew to half the height. 371 00:35:41,630 --> 00:35:45,270 Now dwarf wheat may not sound very revolutionary, 372 00:35:45,270 --> 00:35:51,150 but it was about to trigger the most seismic social change in modern times. 373 00:35:53,630 --> 00:35:57,190 Norin 10 is a natural genetic aberration. 374 00:35:58,470 --> 00:36:00,390 It is a mutation. 375 00:36:01,550 --> 00:36:08,550 In 1953, Borlaug sees a practical application for the insights of Bateson and Vavilov, 376 00:36:08,550 --> 00:36:13,070 a way to use Norin 10 to produce a new plant 377 00:36:13,070 --> 00:36:15,630 with just the characteristics he needs. 378 00:36:16,710 --> 00:36:20,190 Borlaug crosses his top-heavy Mexican variety 379 00:36:20,190 --> 00:36:22,710 with the stumpy Japanese variety... 380 00:36:22,710 --> 00:36:29,350 and creates a short plant with nutritious seed heads. 381 00:36:29,350 --> 00:36:31,750 Let's see what the advantage of that was. 382 00:36:34,150 --> 00:36:38,390 If this weight simulates a gust of wind, 383 00:36:38,390 --> 00:36:41,430 then if we hang it on this tall plant... 384 00:36:42,670 --> 00:36:45,430 Ah! Broken. 385 00:36:46,710 --> 00:36:48,470 On the other hand... 386 00:36:49,990 --> 00:36:54,150 ..if we hang the same weight on the short plant... 387 00:36:57,470 --> 00:37:00,390 ..the stem doesn't break and the plant doesn't fall over. 388 00:37:02,710 --> 00:37:04,510 Small change for a plant, 389 00:37:04,510 --> 00:37:06,430 giant leap for mankind. 390 00:37:29,190 --> 00:37:31,710 Borlaug's wheat sweeps across the world. 391 00:37:34,030 --> 00:37:38,470 In 1966, he takes it to the Indian subcontinent. 392 00:37:43,190 --> 00:37:46,350 Since the successful introduction of dwarf wheat, 393 00:37:46,350 --> 00:37:50,430 India has not once experienced a national famine. 394 00:37:53,150 --> 00:37:57,430 Borlaug's extraordinary success is given the name... 395 00:37:57,430 --> 00:38:00,150 the green revolution. 396 00:38:03,750 --> 00:38:06,470 The increased yields come at a cost. 397 00:38:06,470 --> 00:38:10,670 Higher inputs of fertiliser and water, 398 00:38:10,670 --> 00:38:14,070 some people say it's not sustainable for ever... 399 00:38:14,070 --> 00:38:21,550 but it is clear that this dwarf wheat is the most important plant mutation in the history of civilisation, 400 00:38:21,550 --> 00:38:28,670 because, armed with it, Norman Borlaug took 1,000 million people out of starvation. 401 00:38:29,950 --> 00:38:34,750 In 1970, Borlaug was awarded the Nobel Peace Prize. 402 00:38:36,230 --> 00:38:42,390 His work showed the immense impact of plant genetics on humanity's ability to produce food. 403 00:38:49,790 --> 00:38:53,270 But like Bateson, Wheldale and Vavilov before him, 404 00:38:53,270 --> 00:38:59,310 Borlaug relied on endless crossbreeding and observation to create his new hybrids. 405 00:39:02,510 --> 00:39:06,310 And there was an even more fundamental limitation... 406 00:39:07,910 --> 00:39:13,470 ..Borlaug's success with dwarf wheat was down to the exploitation of a useful mutation 407 00:39:13,470 --> 00:39:15,390 that had occurred by chance. 408 00:39:18,270 --> 00:39:23,190 In the end, the green revolution came down to nature's lucky mistake. 409 00:39:28,270 --> 00:39:31,350 Plant breeders faced one big problem. 410 00:39:31,350 --> 00:39:36,350 They had to rely on nature to provide them with the raw materials, 411 00:39:36,350 --> 00:39:40,630 that one-in-a-million useful mutation that they could exploit. 412 00:39:40,630 --> 00:39:43,510 What if they could cut out nature 413 00:39:43,510 --> 00:39:47,710 and design, engineer the plant they wanted, 414 00:39:47,710 --> 00:39:52,030 one that could survive in a hostile environment or resist a disease? 415 00:39:52,030 --> 00:39:55,430 This is a monumental task, 416 00:39:55,430 --> 00:40:00,910 because to do it they have to control the genes. 417 00:40:02,590 --> 00:40:08,430 The botanists' Holy Grail was a new generation of crops made to order. 418 00:40:08,430 --> 00:40:13,790 Crop breeders needed precision control over plant genes. 419 00:40:16,910 --> 00:40:19,830 A decade after the green revolution, 420 00:40:19,830 --> 00:40:24,510 that control of genes remained as elusive as it had always been. 421 00:40:31,670 --> 00:40:35,230 What comes to mind if I say "sweetcorn"? 422 00:40:36,310 --> 00:40:42,750 Is it ranks of identical, pale, yellow seeds, 423 00:40:42,750 --> 00:40:45,190 like the ones you buy at the greengrocer? 424 00:40:47,030 --> 00:40:49,430 Now, this is wild corn. 425 00:40:50,910 --> 00:40:53,470 And this is amazing! 426 00:40:53,470 --> 00:40:56,750 This is really, really different. 427 00:40:57,750 --> 00:40:59,390 This looks random. 428 00:41:00,150 --> 00:41:03,790 Look at that! Completely different again. 429 00:41:05,150 --> 00:41:10,110 Almost flame-coloured, looks like it's been burnt almost, it's been cooked already. 430 00:41:10,110 --> 00:41:12,390 It almost looks wrong. 431 00:41:14,750 --> 00:41:17,790 Every one of these is different. 432 00:41:20,350 --> 00:41:26,110 This one's almost getting towards some of the seeds that we get in corn on the cob. 433 00:41:26,110 --> 00:41:30,110 This one, you just would never see in the greengrocer's. 434 00:41:30,110 --> 00:41:34,710 These ones, different again. I've no idea what's inside this one. 435 00:41:37,870 --> 00:41:40,270 It really is worse than pass the parcel. 436 00:41:41,310 --> 00:41:44,750 And there we've got... we've got purple, we've got blue, 437 00:41:44,750 --> 00:41:46,950 we've got dark purple... 438 00:41:49,070 --> 00:41:52,270 Now, 50 years ago, these crazy patterns in corn 439 00:41:52,270 --> 00:41:56,670 set in motion a whole new way of thinking about genetics. 440 00:42:06,670 --> 00:42:12,030 In 1945, tucked away in a corner of Long Island, New York, 441 00:42:12,030 --> 00:42:17,550 you would have found a field of maize that at first glance looks ordinary. 442 00:42:19,990 --> 00:42:26,150 This is the stomping ground of a brilliant botanist who would reveal the inner workings of genes, 443 00:42:26,150 --> 00:42:31,150 and so propel plant genetics into the modern age. 444 00:42:35,550 --> 00:42:38,870 Pacing up and down the rows of plants, cigarette in holder, 445 00:42:38,870 --> 00:42:42,510 is a woman with the kind of biceps you only get from digging. 446 00:42:42,510 --> 00:42:45,910 She trusts nobody else to look after her maize plants, 447 00:42:45,910 --> 00:42:49,110 so she does all of the farm work herself. 448 00:42:50,190 --> 00:42:51,950 She's not a farmer. 449 00:42:51,950 --> 00:42:54,910 Her maize is not there to feed anyone. 450 00:42:57,830 --> 00:43:01,870 She's a geneticist. Her name is Barbara McClintock. 451 00:43:04,390 --> 00:43:06,390 McClintock is obsessed with understanding 452 00:43:06,390 --> 00:43:11,110 how plants pass their characteristics down to the next generation... 453 00:43:13,270 --> 00:43:16,590 ..the same question that fascinated Mendel, Bateson and Wheldale. 454 00:43:19,470 --> 00:43:26,110 McClintock has noticed mutations in her maize that behave in totally unexpected ways. 455 00:43:28,070 --> 00:43:30,310 SHOTS RING OUT 456 00:43:35,150 --> 00:43:39,070 McClintock's only employee is a human scarecrow 457 00:43:39,070 --> 00:43:42,670 in the fields to shoot any birds that threaten her plants, 458 00:43:42,670 --> 00:43:45,590 because she cannot afford to lose a single one. 459 00:43:45,590 --> 00:43:49,270 Each is a rare, one-in-a-billion chance mutation. 460 00:43:49,270 --> 00:43:56,030 She suspects that her maize is the key to something really odd going on in plants. 461 00:43:59,470 --> 00:44:04,230 McClintock is captivated by one strange mutation in particular. 462 00:44:07,310 --> 00:44:09,750 This pattern on the seeds. 463 00:44:09,750 --> 00:44:15,590 It makes her suspect she might need to rewrite the rules of genetics. 464 00:44:21,110 --> 00:44:23,390 Day after day, through the seasons, 465 00:44:23,390 --> 00:44:27,430 she puts transparent bags over the female parts of the maize 466 00:44:27,430 --> 00:44:30,190 to stop them being pollinated by the wrong plant. 467 00:44:30,190 --> 00:44:35,790 She puts paper bags over the male parts from other plants to collect their pollen. 468 00:44:37,310 --> 00:44:41,630 McClintock does this again and again on hundreds of plants. 469 00:44:45,310 --> 00:44:50,630 Then, at the end of the day, when the male parts have shed their pollen, 470 00:44:50,630 --> 00:44:57,350 she takes the paper bag and taps out the pollen on to the female parts of the plants she's protected. 471 00:45:02,670 --> 00:45:05,830 McClintock places a wooden paddle in the ground 472 00:45:05,830 --> 00:45:08,790 to remind her which plant was crossed with which. 473 00:45:08,790 --> 00:45:14,750 She then writes down the information on an index card which she takes back to the lab. 474 00:45:14,750 --> 00:45:19,950 On too many of the cards, she's forced to write, "Pulled up by the birds". 475 00:45:19,950 --> 00:45:22,430 That guy with the gun couldn't have been a very good shot. 476 00:45:22,430 --> 00:45:29,430 And that must have been heartbreaking because each one of McClintock's maize plants is a unique experiment. 477 00:45:30,590 --> 00:45:32,990 Maize in the wild is normally red. 478 00:45:34,590 --> 00:45:37,310 Today the sweetcorn in shops is yellow 479 00:45:37,310 --> 00:45:40,590 because of crossbreeding a mutation in that gene. 480 00:45:41,550 --> 00:45:46,270 But in McClintock's mutant maize, the red colour comes back. 481 00:45:53,470 --> 00:45:57,230 Geneticists at the time think they understand mutations... 482 00:45:57,230 --> 00:46:00,070 it all seems pretty simple. 483 00:46:00,070 --> 00:46:05,150 When a gene is working as it should, it's like a light shining, 484 00:46:05,150 --> 00:46:11,590 but when a mutation occurs, and the gene stops working, the light goes out. 485 00:46:12,430 --> 00:46:14,830 There may be any number of explanations for this. 486 00:46:14,830 --> 00:46:16,550 Maybe the filament has blown... 487 00:46:17,430 --> 00:46:19,470 Or the bulb is cracked. 488 00:46:19,470 --> 00:46:20,470 SMASH! 489 00:46:20,470 --> 00:46:22,190 Or the wiring's faulty. 490 00:46:22,190 --> 00:46:26,710 But whatever the reason, the important thing is, they believe, 491 00:46:26,710 --> 00:46:29,470 the light can never go back on. 492 00:46:30,830 --> 00:46:34,790 But McClintock's maize mutation is different, 493 00:46:34,790 --> 00:46:40,430 because in many of her plants it seems to revert spontaneously back to normal. 494 00:46:41,910 --> 00:46:46,270 A mutation reverting back to normal should be impossible, 495 00:46:46,270 --> 00:46:49,310 like a broken light bulb suddenly coming back on. 496 00:46:52,030 --> 00:46:54,230 So she needs to isolate the mutation, 497 00:46:54,230 --> 00:46:57,550 a procedure she's done a thousand times before. 498 00:46:57,550 --> 00:47:00,750 It should not be hard. But this time it's different 499 00:47:00,750 --> 00:47:04,910 because the mutation seems to be in two places at the same time. 500 00:47:04,910 --> 00:47:07,070 And that should be impossible. 501 00:47:07,070 --> 00:47:13,710 She is baffled. And her interest in the mutation begins to become obsessional. 502 00:47:15,190 --> 00:47:19,830 That winter, after thousands of crossbreeding experiments, 503 00:47:19,830 --> 00:47:24,150 all that counting, McClintock must have been exhausted. 504 00:47:24,150 --> 00:47:28,790 But still her mutation makes no sense to her. 505 00:47:29,910 --> 00:47:33,030 If it had been me, I'd have gone over the edge. 506 00:47:34,550 --> 00:47:37,550 The frustration eventually gets to McClintock. 507 00:47:37,550 --> 00:47:39,870 She has a minor breakdown. 508 00:47:40,950 --> 00:47:44,070 Then, one evening, after three years of work, 509 00:47:44,070 --> 00:47:47,230 it all begins to make sense. 510 00:47:49,310 --> 00:47:52,990 McClintock finally understands what is going on. 511 00:47:54,230 --> 00:47:56,910 Like the early geneticists before her, 512 00:47:56,910 --> 00:48:01,110 McClintock cannot see what is happening to the genes in her maize. 513 00:48:01,110 --> 00:48:04,790 What she discovers is a feat of logic. 514 00:48:06,950 --> 00:48:13,750 McClintock deduces that her mutation can be turned on and off, 515 00:48:13,750 --> 00:48:19,710 that its appearance must be controlled by some kind of switch. 516 00:48:21,110 --> 00:48:23,150 Mutations that switch on and off. 517 00:48:25,510 --> 00:48:30,830 McClintock showed that genes are part of a dynamic, shifting system, 518 00:48:30,830 --> 00:48:36,030 and, most importantly, that genes are under the control of switches. 519 00:48:38,910 --> 00:48:42,550 McClintock's vision was revolutionary. 520 00:48:45,470 --> 00:48:46,870 Bateson, 521 00:48:46,870 --> 00:48:48,270 Wheldale, 522 00:48:48,270 --> 00:48:50,070 Vavilov, 523 00:48:50,070 --> 00:48:51,830 Borlaug... 524 00:48:51,830 --> 00:48:59,070 before McClintock geneticists thought that genes were passed passively from generation to generation. 525 00:49:02,830 --> 00:49:06,310 McClintock blew that idea out of the water. 526 00:49:13,030 --> 00:49:18,270 She saw that plants could switch their genes on or off when needed... 527 00:49:19,550 --> 00:49:22,550 ..a mechanism for plants to fine-tune their behaviour 528 00:49:22,550 --> 00:49:24,990 to survive everything the world throws at them. 529 00:49:34,550 --> 00:49:39,670 A new level on which genes work in the world of plants. 530 00:49:48,310 --> 00:49:55,390 And yet, for 20 years, geneticists resisted McClintock's work as being outlandish. 531 00:49:55,390 --> 00:50:03,630 The discovery of DNA structure in 1953 and proof of gene switches in 1961, 532 00:50:03,630 --> 00:50:09,350 would give botanists new tools to control the gene switches McClintock revealed. 533 00:50:12,630 --> 00:50:18,470 I've watched as that DNA technology has transformed plant science during my career. 534 00:50:23,510 --> 00:50:27,550 Geneticists have isolated thousands of different genes. 535 00:50:27,550 --> 00:50:30,470 They can turn genes on and off 536 00:50:30,470 --> 00:50:34,070 and move them between organisms. 537 00:50:35,390 --> 00:50:40,030 Most of us know this as genetic modification, GM. 538 00:50:42,150 --> 00:50:48,710 Genetic modification is loaded with prejudice and misinformation, 539 00:50:48,710 --> 00:50:56,190 so it's very easy to forget how it fits into the story of genetics and agriculture 540 00:50:56,190 --> 00:50:58,190 and civilisation. 541 00:50:59,630 --> 00:51:04,110 For 10,000 years, we have been creating new plants 542 00:51:04,110 --> 00:51:07,110 by putting pollen where pollen should never go 543 00:51:07,110 --> 00:51:11,070 and by selecting and preserving mutations. 544 00:51:11,070 --> 00:51:19,190 And as a result of the efficient way that we grow our crops in large monocultures, 545 00:51:19,190 --> 00:51:24,230 these plants are susceptible to pests and diseases. 546 00:51:24,230 --> 00:51:28,550 Now, if we can build stronger, more efficient plants, 547 00:51:28,550 --> 00:51:31,990 then they will be able to fight off those pests and diseases, 548 00:51:31,990 --> 00:51:34,390 and their yield will go up. 549 00:51:35,590 --> 00:51:40,030 Certainly there may be risks attached to genetically modified plants, 550 00:51:40,030 --> 00:51:42,750 but it is a known risk 551 00:51:42,750 --> 00:51:48,590 that people are dying of starvation because we cannot produce enough food. 552 00:51:48,590 --> 00:51:52,790 And that situation is not going to improve as population grows. 553 00:51:54,950 --> 00:51:59,950 So far I believe GM has failed to address mass hunger. 554 00:52:02,510 --> 00:52:04,830 But that may be about to change. 555 00:52:06,550 --> 00:52:11,550 A global consortium of labs has launched has launched one of the most ambitious attempts ever 556 00:52:11,550 --> 00:52:13,430 to tackle world hunger. 557 00:52:15,190 --> 00:52:20,390 Jane Langdale at the Plant Sciences labs in Oxford runs one of the teams. 558 00:52:22,790 --> 00:52:27,070 Her aim is to revolutionise the productivity of rice. 559 00:52:28,750 --> 00:52:31,550 So, Jane, why is rice important? 560 00:52:31,550 --> 00:52:33,270 Rice is an incredibly important crop. 561 00:52:33,270 --> 00:52:36,150 90% of the rice that is grown in the world 562 00:52:36,150 --> 00:52:39,630 is eaten by the people who grow it. By the farmers? Yes. 563 00:52:39,630 --> 00:52:43,550 They use it directly for food. They don't feed it to animals, they don't use any of it for heating 564 00:52:43,550 --> 00:52:45,270 or anything. They actually eat it. 565 00:52:45,270 --> 00:52:50,470 Right now, you can grow a hectare of rice and you will feed 27 people. 566 00:52:50,470 --> 00:52:56,030 OK. By 2050, you've got to feed 43 people from that same land area, 567 00:52:56,030 --> 00:52:58,630 and you've got to use less fertiliser, 568 00:52:58,630 --> 00:53:02,430 there'll be less predictable rainfall and water 569 00:53:02,430 --> 00:53:07,630 and probably there'll be increasing competition to use that land for something else. Yeah. 570 00:53:07,630 --> 00:53:09,910 So it's a big problem. 571 00:53:13,110 --> 00:53:20,310 For the last 40 years, rice production has kept pace with the increase in population. 572 00:53:20,310 --> 00:53:26,190 But we have reached the limit of how much can be achieved with existing farmland and fertiliser. 573 00:53:27,990 --> 00:53:32,350 A radical new strategy is needed if billions are to survive. 574 00:53:37,150 --> 00:53:41,950 Jane Langdale wants to change the way rice does photosynthesis. 575 00:53:43,550 --> 00:53:48,430 Like all plants, it uses sunlight, carbon dioxide and water to make sugar. 576 00:53:49,830 --> 00:53:54,350 But rice does this very inefficiently in hot, dry climates. 577 00:53:54,350 --> 00:53:59,990 Langdale hopes to redesign rice to make it as efficient as maize. 578 00:54:01,670 --> 00:54:06,190 To me, the leaves of maize and rice look pretty similar, 579 00:54:06,190 --> 00:54:09,990 so how difficult can it be to make rice more like maize? 580 00:54:09,990 --> 00:54:12,230 If we are to achieve our goal 581 00:54:12,230 --> 00:54:15,110 of converting rice into maize-type photosynthesis, 582 00:54:15,110 --> 00:54:21,030 then we've got to completely change the internal architecture of this leaf to look like this one. 583 00:54:21,030 --> 00:54:24,390 We've got to completely change the biochemistry. It's not trivial. 584 00:54:26,270 --> 00:54:34,390 Photosynthesis in maize depends on those cells that surround the many veins inside their leaves. 585 00:54:35,630 --> 00:54:38,630 OK, so if we just focus this a little bit... 586 00:54:38,630 --> 00:54:42,190 and then I can show you on the screen here, 587 00:54:42,190 --> 00:54:44,590 and you can see that the veins are stained pink, 588 00:54:44,590 --> 00:54:49,390 you can see that there's two large veins there and there's about 20 cells in between the two. 589 00:54:49,390 --> 00:54:53,030 Whereas, if we look at the regular leaf above, you can see a major vein here, 590 00:54:53,030 --> 00:54:58,950 but then you can count one, two, three, four, five veins in the same gap as there is with that one. 591 00:54:58,950 --> 00:55:03,790 So this is essentially what the rice leaf looks like, and we need to make it look like this. 592 00:55:03,790 --> 00:55:06,270 We need these more regular veins, 593 00:55:06,270 --> 00:55:09,150 because unless that pattern is there in the leaf, 594 00:55:09,150 --> 00:55:13,150 then the rice leaf will not be able to photosynthesise like maize. 595 00:55:18,070 --> 00:55:23,030 Langdale's team is trying to unpick the sequence of gene switches 596 00:55:23,030 --> 00:55:26,830 that allows maize to make more veins in its leaves. 597 00:55:31,110 --> 00:55:35,030 The switches are flipped in the very early stages of life, 598 00:55:35,030 --> 00:55:43,430 so the only way to study the process is by teasing out tiny patches of growing cells, buried in the stems. 599 00:55:48,350 --> 00:55:50,430 It's delicate, skilled work. 600 00:55:59,670 --> 00:56:03,150 So I'm bewildered that Jane's asked me to give it a go! 601 00:56:03,150 --> 00:56:06,310 Pull it out. Pull it out? OK. There we go. Right. 602 00:56:06,310 --> 00:56:08,430 So we've got our young plant, so... 603 00:56:08,430 --> 00:56:11,990 Right, so if you just put it on the... I'm looking for something inside there? 604 00:56:11,990 --> 00:56:14,350 Inside there, yes. How big is it? 605 00:56:14,350 --> 00:56:16,750 Ish? You know, to the nearest millimetre? 606 00:56:16,750 --> 00:56:19,750 To the nearest millimetre? It's not even close to a millimetre! OK! 607 00:56:22,230 --> 00:56:24,230 How am I going to recognise it when I see it? 608 00:56:24,230 --> 00:56:26,470 I'm going to tell you it's there. 609 00:56:29,150 --> 00:56:33,230 Now, be careful. Yeah. If you make a big cut like that... I'm being incredibly careful. 610 00:56:33,230 --> 00:56:36,150 ..you might go straight through the main shoot. 611 00:56:39,710 --> 00:56:43,310 It's very much like cutting up an onion, isn't it, for tea? No. 612 00:56:45,590 --> 00:56:48,350 Careful. I am being careful. 613 00:56:50,030 --> 00:56:53,630 Is it in there? Wait, stop! Stop, stop, stop! 614 00:56:53,630 --> 00:56:55,830 Increase the magnification if you can. 615 00:57:00,350 --> 00:57:02,070 Is that it? No. 616 00:57:02,070 --> 00:57:06,710 Is it further in still? Believe me, I'll scream if you get to it. 617 00:57:08,630 --> 00:57:10,150 Uh-huh...! 618 00:57:12,550 --> 00:57:13,910 Oh! 619 00:57:13,910 --> 00:57:17,390 I hate to say this, but I think you just lost it. 620 00:57:17,390 --> 00:57:18,950 Oh! 621 00:57:18,950 --> 00:57:20,590 Is it that? Yeah. 622 00:57:22,110 --> 00:57:24,990 Is that it, the middle one that I've just gone through there? 623 00:57:24,990 --> 00:57:26,710 Yeah. Oh, sod it! 624 00:57:28,190 --> 00:57:36,190 For a single experiment, Langdale's team needs to dissect 500 tiny balls of cells 625 00:57:36,190 --> 00:57:40,350 of the kind I took two hours to turn into a mush. 626 00:57:41,510 --> 00:57:45,790 Each phase of this project seems to me monumental. 627 00:57:51,270 --> 00:57:56,070 The first green revolution used plant-breeding techniques 628 00:57:56,070 --> 00:57:59,150 that we'd been exploiting for thousands of years. 629 00:57:59,150 --> 00:58:05,790 The next revolution, starting in Jane Langdale's lab and in other labs around the world, 630 00:58:05,790 --> 00:58:11,950 is exploiting a deeper understanding of genetics. 631 00:58:11,950 --> 00:58:14,310 And it may be a long shot, 632 00:58:14,310 --> 00:58:22,550 but the target of feeding 9,000 million people has to make it worthwhile. 633 00:58:26,310 --> 00:58:30,390 Subtitles by Red Bee Media Ltd 634 00:58:30,390 --> 00:58:34,390 E-mail subtitling@bbc.co.uk