1 00:00:00,360 --> 00:00:02,180 I think it's time we got explicit about the 2 00:00:02,180 --> 00:00:06,340 physical processes that lead to genetic variability and the physical 3 00:00:06,340 --> 00:00:08,550 passing on of our genes. Now if you want to 4 00:00:08,550 --> 00:00:11,740 have your own biological children, there's a pretty important event 5 00:00:11,740 --> 00:00:16,167 that must precede the presence of children. instead of thinking 6 00:00:16,167 --> 00:00:18,675 of you having your own children lets just think about 7 00:00:18,675 --> 00:00:22,560 you, right. Here I am pretty happy, 30 years old. 8 00:00:22,560 --> 00:00:25,580 But where did I come from? About 30 years ago, 9 00:00:25,580 --> 00:00:28,220 I was in my mother's womb developing as an 10 00:00:28,220 --> 00:00:31,240 embryo and then fetus. But where did I come from 11 00:00:31,240 --> 00:00:34,750 before that? About nine months before I was born, I 12 00:00:34,750 --> 00:00:38,340 was conceived meaning that the sex cells from my parents, 13 00:00:38,340 --> 00:00:40,940 the sperm fertilized the egg and I received my 14 00:00:40,940 --> 00:00:44,354 very first cell with a full genome. Half from mom, 15 00:00:44,354 --> 00:00:47,720 half from dad. And of course about 30 minutes to 16 00:00:47,720 --> 00:00:50,990 one full day before conception, there was a pretty important 17 00:00:50,990 --> 00:00:54,590 physical interaction my biological mother and biological father 18 00:00:54,590 --> 00:00:58,510 had to go through, the act of sexual intercourse. 19 00:00:58,510 --> 00:01:00,830 For me to be here today, standing here, teaching 20 00:01:00,830 --> 00:01:03,330 this course to you. All three of these previous 21 00:01:03,330 --> 00:01:05,970 events must have happened. My parents must have found 22 00:01:05,970 --> 00:01:09,570 each other and exchanged sex cells. They must have 23 00:01:09,570 --> 00:01:13,060 had a successful fertilization of these sex cells. And 24 00:01:13,060 --> 00:01:16,050 they must have had a successful development in utero, 25 00:01:16,050 --> 00:01:20,490 or growing in my mother's womb. Now while I owe a lot to my mom and dad for 26 00:01:20,490 --> 00:01:23,670 bringing me into this world, I really owe their 27 00:01:23,670 --> 00:01:28,100 sex cells. Or what we call gametes. Gametes are 28 00:01:28,100 --> 00:01:30,790 either sperm or eggs, sperm in male, eggs in 29 00:01:30,790 --> 00:01:35,320 females. And germ cells make gametes. Germ cells are 30 00:01:35,320 --> 00:01:38,500 the precursors to the sex cells. And in this 31 00:01:38,500 --> 00:01:41,950 case the word germ. Doesn't mean germ like bacteria 32 00:01:41,950 --> 00:01:46,110 it means germ like germination, like a flower. 33 00:01:46,110 --> 00:01:48,020 The cells that make our gametes are called 34 00:01:48,020 --> 00:01:50,740 germ cells because they are the seed for 35 00:01:50,740 --> 00:01:54,850 our germination. So understanding how germ cells make 36 00:01:54,850 --> 00:01:58,450 gamete is a really critical component to understanding 37 00:01:58,450 --> 00:02:01,550 which alleles you're going to get from which parent. 38 00:02:01,550 --> 00:02:02,670 Let's talk a little bit more about how 39 00:02:02,670 --> 00:02:04,710 that process of cell division is going to occur.