 Now, let's get ourselves to Metaphase 1. If you look at our to-do list, you'll see that we're going to talk about Metaphase 1 and a thing called independent assortment, but let's get to Metaphase and then see if we can figure out what independent assortment is. Finishing prophase in our little visual here, here we go. Our centrioles are creating spindle fibers that start attaching to our pairs of homologs. And this is all still prophase 1 or prometaphase 1, like whatever. But look, our spindle fibers are lining up homologous pairs on the Metaphase plate. If we took each one of these homologs and separated them and spread them out in a line, that's mitosis. Because the homologs are connected to each other, we know we're in meiosis 1. Can you predict what's going to happen in anaphase 1? I guarantee you can, but before we go, okay, well never mind. Let's do predict what's going to happen in anaphase 1 of meiosis. Homologs are going to split. In fact, I'm just going to show it to you because, look, it took one slide to show you that our homologs are going to split and go to the poles. But this thing that I said, this independent assortment is going to happen in metaphase 1. And I want you to look at this and think about, okay, what could independent assortment be? Here's your clue. Is this the only way that these homologous pairs could line up on the Metaphase plate? Is this it? Will they always line up with sperm parent, egg parent on the top pair, then egg parent, sperm parent, and egg parent, sperm parent on everything else? Do you see what I'm saying? Okay, I'm moving us away from this. I have to figure out how to do this. Okay, I can do this. I'm moving us to same thing. But what are all the possible ways? We can line up on the Metaphase plate. I think you have to draw it out to convince yourself that this is true. In independent assortment, the homologs line up on the Metaphase plate independently. They might line up this way, or they might line up this way. And every single one of them flips that coin and takes a chance about which side it ends up on. So take a look at this, and I'm going to give you a task. Here are the same, the same three different chromosomes. Match them up with their homolog, and line them up on the Metaphase plate. And how many different ways can you line them up? What are all the possible ways you can line three chromosomes up on the Metaphase plate? Push pause and give yourself that challenge, and see if you can figure anything out. I am not going to push pause, I'm going to just show you the possible ways. Look at this. Do you agree that all the sperm parent and all the egg parent can line up on one side as illustrated in cell number one? Sure. Why not? It's a flip of the coin. Now think about this. Okay, somebody else is going to have to do the probability work here. You could calculate the probability that all 23 of the chromosomes from your egg parent came from their egg parent. It's not very likely. That's like, I mean, if that were the case, you should go buy a lottery ticket. Because that's like the probability of that happening would be really small. But the probability of any of this happening is like so wild. Because we can have them, that is possible. That's one arrangement. Now something I want you to think about, you might have gone, well there's another arrangement, all red on the right and all blue on the left, whatever. I said that backwards because I can't tell my right from my left. But you know what I mean, the opposite of that. But that's going to result in the same gametes. Can you visualize that? Can you finish meiosis? Imagine separating homologues. What's going to happen in meiosis? Two separating sisters just like mitosis. And if you imagine all those separations, you can end up with two gametes with all blue and two gametes with all red. And whether you line them up this way or this way, it's the same orientation. Are you good? This took me a really long time to fiddle with and prove to myself that that was true. So I can tell you this with assurance. Do you agree that that's another way we could line up? And then the possible gametes are different. Because of crossing over, because of independent assortment, each gamete is like crazy different. That's another possible arrangement. And then of course, you could have this one too. It take like, how do you feel about that? It might take some fiddling to go like, okay, I see that. And it might take just two chromosomes, like draw it out with two chromosomes and convince yourself that how the chromosomes line up on the metaphase plate impacts the gametes that are possible. I'm just going to say one more thing. I promise that's it. Just one more. This right here, this independent assortment, is how we are going to tackle heredity problems moving forward. So all the rest of our lectures in this section rely on your understanding of this moment, this concept of independent assortment. You will be so happy if you believe me and make sure this is cozy to you, this idea of how we line things up. Okay, let's go through the rest of the process. Let's finish meiosis and watch everything that happens in the rest of the process.