 Myosis 1, we're going from one diploid cell to two haploid cells. And the amazing thing that I'm going to tell you is this. In myosis 1, the stages are exactly the same as the stages of mitosis. This is good, bad. I think it's awesome because it makes it, for me, my brain goes, oh, that's easy. I love to memorize new things, but there are some distinctive differences, so maybe it will be confusing for you. Don't let it be confusing. Go study mitosis till you're comfortable. So we have prophase one. Now, if you call prophase one, prophase, you're talking about mitosis and you will get questions incorrect. If you call myosis flat-out prophase, whatever I just said, you know what I mean. It has to be prophase one. It's not prophase two. It's not prophase 12. It's prophase one. So what do you think the next stage is? Metaphase one, anaphase one, and telophase one. Those are all part of myosis one. I'm going to mark only the differences, only the things that make myosis different from mitosis. Everything else you can assume is the same. For example, start listing off some things that happen in prophase of mitosis. Chromosomes condense happens in myosis as well. Nuclear envelope disappears. Totally happens in myosis as well. Centrosomes arrive. Totally happens in mitosis as well. So I'm going to make a list of only the things that happen uniquely in prophase one of myosis one. First of all, unique homologous chromosomes hook up. Homologous chromosomes hook up in mitosis. All we did is we had our homologs and they just like whatever, they hung out totally separately in myosis. My homologs literally hook up. They're like, dude, how's it going, my homolog? The homologs in the house. And they hang out together. There's no other way to say it, they hook up. Guess what else they do? You're not going to believe this. This is so cool. It's called crossing over, but they swap parts. True story. I am making this stuff up. Look, these homologs swap equal parts. They don't swap like, here, I'll give you the eye color gene. They don't give me the skin color gene. No, no, no, no. They don't even, like, they're not even going to talk about that. Anybody who does that is going to die. So, you know what, anybody who does that is going to be eliminated from the gene pool real fast. So they swap equal parts. Hey, I've got the blue eye color gene over here, but I see you have the brown eye color gene. I'd like to try the brown eye color gene. They swap, and then they switch pieces of DNA. And all the genes that are in that piece of DNA switch. Now, if I were to switch, like, I would not trade an arm for a leg. I would trade an arm for an arm, but I'll totally go for somebody's buff, like, humongous, even though, I mean, that's humongous and buff, but I'd be cool with having a little bit bigger of a bicep. So I'll trade somebody's arm for a bigger bicep. That's awesome. And I still have an arm. So, I'm totally cool, right? Makes complete sense. Crossing over. How cool is that? Let's see, what else happens? The homologs in metaphase one, it's the homologs that line up on the metaphase plate. So, homologs line up on metaphase plate. Again, my sister's lined up last time, but now my homologs are going to line up together. So, where metaphase, I mean, mitosis, seriously. In mitosis, they lined up, this is meiosis. But in mitosis, they lined up like this. They lined up in a line, like this. In meiosis, they lined up like this. So, my homologs are lined up on the metaphase plate. Talk to me, dog pounds, what do you think's going to happen next? Who splits? It's different, the homologs split. In mitosis, my sister's split. In meiosis one, my homologs split apart. Can you visualize how if I split homologs, here's a centromere and here's a centromere. And I literally divide the total number of centromeres in half. So, that is why meiosis one results in two haploid nuclei. Now, there's something else I was going to say about the homologs split. Yeah, yeah, yeah. Okay, I think that's good. Sometimes after meiosis one, we return to like a phase type state before going into meiosis two. Sometimes we don't. Sometimes we don't even go through cytokinesis. Sometimes the nuclei just go through meiosis again and then we end up with cytokinesis. So, there's lots of different ways to do this. The bottom line is that now, let's just for ease, let's say we've got two haploid nuclei and let's go through cytokinesis. And the cytokinesis, here we are. So, we've got two new cells and they're haploid. These two cells are both going to go through meiosis two.