 Okay, so now what we're going to do is talk about the process of meiosis. Meiosis is going to happen only in gametes, so the production of gametes happens from meiosis. You guys are like, isn't that the same thing? Meiosis is completely different from meiosis because with meiosis you only have one division, but with meiosis you have two. So what we have to do is we have to create four genetically variable daughter cells which will go on to become sperm and egg. They have to be half number because if they have the complete number, then when you join them together at fertilization, you end up with an individual that has way too many chromosomes. So we have to cut the number in half, and the only way to do that is by having two sequential divisions. Okay, so what we're going to do is we're going to run through both stages of meiosis. You'll see that the phases that we saw in mitosis are the same, it's just that we repeat them. So we're going to go through it one time and then we're going to continue on, and that's what makes meiosis so special. Okay? So we're starting off in our cell. You can see that the cell has their loosely configured chromosomes. Remember these chromosomes are very loosely configured and they are malleable, meaning that I can move them around, or rearrange them however I see fit. But for this demonstration you also notice that they're holding a marker in their hands. This marker is going to represent an allele, and the top is going to be that particular variation of allele. So what we're going to do is dominate, red will be recessive. So they're each showing that they contain at least one allele even though there are more. So first thing we have to do, duplicate all the DNA, right, happens during interphase. So here comes our second string of chromosomes. Now we have replication here on the male side, replication of the female side, all within the same chromosome. For a meiosis purpose, we call this configuration a tetrad, because there's one, two, three, four. Okay? So we have interphase, where we duplicate, okay? We have prophase, where everything condenses together, right? The nuclear envelope that was around these guys is going to disappear, meaning that the nucleus is now open to the rest of the cell. So we have two centrioles who start off as a pair and separate one moving to either side of our cell, okay? Now what we have to do is we move into metaphase. Metaphase is where they're going to line up in the middle. So once again, everyone line up in the middle, chromosomes, okay? So you can see that they're all lined up in the middle. But what you can't see, and I'm going to try to make more clear, is that during this process where they're all contained close together, there could be a crossing over event that happens. Meaning that the DNA from one chromosome could interlock and switch places with the DNA on another chromosome, okay? And the way that we're going to show this is that the red allele from the mom is going to cross over and switch places with the blue allele from the dad, okay? So you can see that these alleles are now genetically different. Once the crossing over has happened, we're going to move into anaphase, which is where the centrioles grab their chromosomes and separate up, moving to opposite sides of the cell, okay? Now that we have separated, we have to continue on and we have to divide the cell with telephase. Telephase is going to be the opposite of prophase, which is going to be where the nucleus is going to reform, right? The organelles that have been replicated will divide up as well, okay? And we condense down to form two identical, I'm sorry, two genetically variable daughter cells. This is different than mitosis because with mitosis, they were the same. But because of that crossing over event, we now have genetic variability, okay? So picking up where we left off, we went ahead and took one of those daughter cells and kind of moved them out of the way so that we could focus on the other daughter cell, okay? When we look closely at the daughter cell, we have the DNA that's in the nucleus, right? We do have one strand that's mom, one strand that's dad. You can see if they all hold their alleles out in front of them, okay? That we no longer have the same. We've got one red that has a blue top, two blue, one red. So we're getting some genetic variability just in this one stage. But we have to finish mitosis. So the steps are all the same. We just skip the reproduction of DNA. We don't go through interphase. We start right at prophase, okay? So during prophase, you guys condense down. Chromosomes condense down. The centrioles come out and move to either side, okay? Now that we have that happen, we're gonna go ahead and we're gonna have metaphase. Metaphase is where you guys line up in the middle, okay? All right? Now that they're all lined up in the middle, right, we have anaphase where they pull apart. So centrioles grab your chromosomes and pull them apart, okay? You, and you go this way, you, and you go that way, okay? Anaphase, we've separated them up, okay? Now we have to separate up the organelles as well, okay, on the side. So what we'll have is going to be four genetically variable daughter cells. So now we can look at the products. We have four cells that have been produced. Each of these are haploid, meaning they only have half the number of chromosomes. And what I wanted to show you is that they are now all genetically different, okay? You've got one cell that's all blue and then blue and red. You've got another cell that's red, okay? Another combination of blue and red, okay? You've got one that's red and blue completely, and another one that's red and blue for different chromosomes, okay? So what we do now is we have four genetically different cells that are going to go on and go through the fertilization event to create you.