1 00:00:00,000 --> 00:00:06,570 2 00:00:06,570 --> 00:00:08,920 PROFESSOR: Hello and welcome to the help session on 3 00:00:08,920 --> 00:00:10,220 complementation. 4 00:00:10,220 --> 00:00:13,140 Today, we will briefly be reviewing the concept of 5 00:00:13,140 --> 00:00:14,400 complementation. 6 00:00:14,400 --> 00:00:16,870 And then, we will discuss complementation with a 7 00:00:16,870 --> 00:00:19,320 non-biological example. 8 00:00:19,320 --> 00:00:24,250 So to begin, complementation is generally used to determine 9 00:00:24,250 --> 00:00:28,090 if two mutations fall in the same gene or if they fall in 10 00:00:28,090 --> 00:00:29,390 different genes. 11 00:00:29,390 --> 00:00:33,470 So here, we have two mutants-- mutant one and mutant two. 12 00:00:33,470 --> 00:00:36,820 Both of these have mutations in the 13 00:00:36,820 --> 00:00:38,880 lysine biogenesis pathway. 14 00:00:38,880 --> 00:00:42,390 So on their own, they cannot produce lysine. 15 00:00:42,390 --> 00:00:45,820 To determine if these mutations fall in the same 16 00:00:45,820 --> 00:00:49,710 gene or in different genes, we need to cross the two mutants 17 00:00:49,710 --> 00:00:53,250 together and examine their progeny. 18 00:00:53,250 --> 00:00:58,040 If the progeny can grow, this means that the two mutations 19 00:00:58,040 --> 00:01:01,010 were in different genes, and thus, they 20 00:01:01,010 --> 00:01:03,160 complement each other. 21 00:01:03,160 --> 00:01:08,690 However, if the progeny cannot grow, this means that the two 22 00:01:08,690 --> 00:01:12,730 mutations were in the same gene, and they do not 23 00:01:12,730 --> 00:01:14,910 complement each other. 24 00:01:14,910 --> 00:01:16,550 So now, let me explain 25 00:01:16,550 --> 00:01:18,570 complementation yet another way. 26 00:01:18,570 --> 00:01:22,060 27 00:01:22,060 --> 00:01:24,770 So over here, we have the knitting pathway. 28 00:01:24,770 --> 00:01:27,330 It's very simple and straightforward. 29 00:01:27,330 --> 00:01:29,575 In order to knit, you need two things. 30 00:01:29,575 --> 00:01:32,290 31 00:01:32,290 --> 00:01:36,200 You need both the knitting needles and you need yarn. 32 00:01:36,200 --> 00:01:39,170 When you have both of these things together, you can knit 33 00:01:39,170 --> 00:01:40,880 a nice scarf. 34 00:01:40,880 --> 00:01:44,200 So to explain how this is related to complementation, I 35 00:01:44,200 --> 00:01:46,645 have brought along my friend Robert to give us a hand. 36 00:01:46,645 --> 00:01:50,980 37 00:01:50,980 --> 00:01:51,800 All right. 38 00:01:51,800 --> 00:01:56,600 So in the first scenario, we're going to have me with 39 00:01:56,600 --> 00:01:59,830 yarn and Robert with needles. 40 00:01:59,830 --> 00:02:05,060 When I have yarn, I can't knit by myself, because I am 41 00:02:05,060 --> 00:02:06,640 lacking needles. 42 00:02:06,640 --> 00:02:09,699 This is equivalent to having a mutation in what we'll call 43 00:02:09,699 --> 00:02:11,840 the gene for needles. 44 00:02:11,840 --> 00:02:16,310 Robert, on the other hand, has needles, but by himself, he 45 00:02:16,310 --> 00:02:17,520 has no yarn. 46 00:02:17,520 --> 00:02:19,460 So he can't knit. 47 00:02:19,460 --> 00:02:22,550 So alone, neither of us are able to knit. 48 00:02:22,550 --> 00:02:26,870 However, if we team up and we work together and we share our 49 00:02:26,870 --> 00:02:32,350 resources, now we have both yarn and needles, so we can 50 00:02:32,350 --> 00:02:35,210 knit a nice scarf. 51 00:02:35,210 --> 00:02:35,810 All right. 52 00:02:35,810 --> 00:02:37,600 So how about the case of non-complementation? 53 00:02:37,600 --> 00:02:42,320 54 00:02:42,320 --> 00:02:47,170 If I have needles now, and Robert also has needles, me by 55 00:02:47,170 --> 00:02:50,770 myself, I cannot knit, because I have a mutation in that I 56 00:02:50,770 --> 00:02:52,590 have to no yarn. 57 00:02:52,590 --> 00:02:57,030 Robert also has needles and he also does not have yarn. 58 00:02:57,030 --> 00:03:00,070 So by himself, he can't knit either. 59 00:03:00,070 --> 00:03:03,800 This time, when we team up and we try to work together, even 60 00:03:03,800 --> 00:03:06,910 if we share our needles, we still can't knit, because we 61 00:03:06,910 --> 00:03:08,080 have no yarn. 62 00:03:08,080 --> 00:03:11,460 So this is the case of non-complementation. 63 00:03:11,460 --> 00:03:14,040 Thanks, Robert. 64 00:03:14,040 --> 00:03:17,210 This concludes the help session on complementation. 65 00:03:17,210 --> 00:03:18,460 Thanks for joining us. 66 00:03:18,460 --> 00:03:20,148