WEBVTT - What Makes Durian Fruit Smell So Bad? 0:00:02.040 --> 0:00:07.080 Welcome to brain stuff from how Stuff Works, Hey, brain Stuff, 0:00:07.160 --> 0:00:10.600 Lauren vogel Bam. Here in Southeast Asia, the Durian is 0:00:10.640 --> 0:00:13.760 called the king of fruits, but not everybody in the 0:00:13.760 --> 0:00:18.480 world bows down to this bulbous, spiny, custardy delicacy. That's 0:00:18.640 --> 0:00:21.720 usually because of the odor. The smell of a ripe 0:00:21.800 --> 0:00:25.400 Daurian has been compared to sweaty socks, road kill, custard, 0:00:25.720 --> 0:00:29.720 rotten eggs, garlic, cheese, a gas leak, and a sewer 0:00:29.800 --> 0:00:33.040 full of rotting pineapples. And it's strong enough that in 0:00:33.120 --> 0:00:36.159 places where it grows, many businesses and public areas have 0:00:36.280 --> 0:00:40.159 pictographic signs up no Duryan, like no smoking, but with 0:00:40.159 --> 0:00:42.680 a spiny ball in the place of the cigarette. But 0:00:42.760 --> 0:00:46.440 still the fruit has its super fans, and now some 0:00:46.600 --> 0:00:49.960 of those super fans, from the National Cancer Center Singapore 0:00:50.080 --> 0:00:53.680 and Duke and US Medical School, along with some financial 0:00:53.680 --> 0:00:57.240 donors who love Durians enough to privately fund study about them, 0:00:57.320 --> 0:01:00.800 have completely mapped the Dairyan genome to find out, among 0:01:00.840 --> 0:01:05.160 other things, why the putrid stench durians. In the study 0:01:05.240 --> 0:01:08.520 published in the journal Nature Genetics, the researchers sequence to 0:01:08.520 --> 0:01:11.800 the genome of a popular and prized daurian variety called 0:01:11.880 --> 0:01:14.720 Mussang King and found its genome is made up of 0:01:14.760 --> 0:01:18.040 around forty six thousand genes, just about double the number 0:01:18.040 --> 0:01:20.840 of genes that compose the human genome. They found the 0:01:20.880 --> 0:01:24.520 plant is closely related to both cotton and cacao. That's right, 0:01:24.600 --> 0:01:27.640 the plant that gives us chocolate. But the researchers were 0:01:27.640 --> 0:01:30.560 really interested in the source of the smell, so in 0:01:30.760 --> 0:01:34.360 snooping around the genome for odor producing compounds, they found 0:01:34.400 --> 0:01:36.560 a class of genes called m g l S that's 0:01:36.600 --> 0:01:40.520 methionin gamma liaises in the leaves, roots, and fruits of 0:01:40.600 --> 0:01:44.320 daurian plants. The researchers found that these genes regulate the 0:01:44.360 --> 0:01:48.840 synthesis of odor producing volatile sulfur compounds or vs cs, 0:01:49.320 --> 0:01:52.440 you know like rotten egg smell. They also discovered that 0:01:52.480 --> 0:01:54.960 in the ripe fruit, the expression of one of these 0:01:55.080 --> 0:01:59.440 VCS expressing genes is about two thousand times stronger than 0:01:59.480 --> 0:02:02.760 another part to the plant in the wild, This aspect 0:02:02.880 --> 0:02:06.520 may be responsible for attracting seed dispersing animals like elephants 0:02:06.520 --> 0:02:09.800 and bats to the Durian fruit. This isn't the first 0:02:09.840 --> 0:02:13.680 research conducted on the durian's unique scent. In a team 0:02:13.680 --> 0:02:17.280 of German researchers identified dozens of chemical compounds that combine 0:02:17.320 --> 0:02:20.400 to create the smell, but that research did not investigate 0:02:20.400 --> 0:02:23.920 the genes behind those compounds. The current research team was 0:02:23.960 --> 0:02:26.760 hoping to make an important medical discovery with the sequencing 0:02:26.800 --> 0:02:30.440 of the Musang king genome. After all, anti cancer drugs 0:02:30.440 --> 0:02:32.799 like taxol derived from the bark of the Pacific u 0:02:33.200 --> 0:02:37.200 save lives every day, and as biodiversity decreases all over 0:02:37.240 --> 0:02:39.320 the world, we need to figure out what we have 0:02:39.480 --> 0:02:43.640 while it's still around. But as Durian enthusiasts, these scientists 0:02:43.720 --> 0:02:47.440 also just wanted to investigate how this quirky and controversial 0:02:47.480 --> 0:02:51.000 plant might be conserved. Besides Mussan king, there are around 0:02:51.040 --> 0:02:54.040 thirty other species of durian, both edible and inedible, in 0:02:54.080 --> 0:02:57.200 the Southeast Asian forests, and some of them are endangered. 0:02:57.800 --> 0:03:01.079 In a press release, co lead author doctor Ben Tian, 0:03:01.360 --> 0:03:04.880 Deputy Director of the National Cancer Center Singapore, wrote, many 0:03:04.919 --> 0:03:06.959 of these other Durian species are in this part of 0:03:07.000 --> 0:03:09.560 the world, and sadly some are endangered due to the 0:03:09.600 --> 0:03:13.639 increasing loss of biodiversity. DNA sequencing is thus an important 0:03:13.639 --> 0:03:17.200 tool to protect the precious information contained in these fascinating 0:03:17.240 --> 0:03:25.600 and important plants. Today's episode was written by Jesselyin Shields 0:03:25.600 --> 0:03:28.440 and produced by Tyler Clang. I've got another podcast called 0:03:28.480 --> 0:03:30.840 food Stuff that explores the science and history of food, 0:03:30.880 --> 0:03:33.000 and we did a whole episode on Durian, so check 0:03:33.040 --> 0:03:35.680 that out if you're still curious, And of course, for 0:03:35.760 --> 0:03:38.640 more on this and lots of other topics about questionable smells, 0:03:38.920 --> 0:03:52.560 visit our home planet, how stuff works dot com.