 Alright, seven characteristics that Mendel looked at in peas, and I just have to say, we should probably name the fact that Mendel pretty much either hit the jackpot, I hope he went out and played the lottery or something, did a little gambling, because he either was the luckiest human on the planet, or he didn't actually report out all his data, and let's just remember he's a monk, so he didn't have his fingers in the actual scientific dialogue, and it wasn't until after he died that people started looking at his research and going like, wait a minute, this is like, whoa, this has some important consequence, this is important research right here. I say he was lucky because the characters that he chose, the seven characters that he chose, are traits coded for by genes, and each gene was on a separate chromosome. I can't remember anything, so I can't remember when we're gonna talk about what happens when genes are not on separate chromosomes, but we will talk about that, they're called linked genes, and if the genes are not on separate chromosomes, we do not see the results that Mendel saw. We see results that we can explain now that we understand what Mendel did, but each one of these traits is carried on a separate chromosome, and the traits that he looked at were seed shape, and color, pod, pea pod, shape, and color, flower color, and flower position, and the height of the plant itself, so the shorty shorts and the tall ones. So let's look at our possible phenotypes for each one of these, and I'm gonna fill in this chart for you, but you will never have to memorize this chart, like I would never give you this chart and be like, okay, fill it in, like what, I could, there's no planet on which I could fill this chart in. I've got my cheat sheet chart right over here, so I know what our possibilities are, and I'm gonna indicate, when we're talking about the phenotypes, the possible phenotypes, I'm gonna indicate which phenotype is dominant. I don't know how I'm gonna do that yet, but I'm gonna tell, maybe I'll list the dominant trait first. For example, in seed shape, our two options are round or wrinkled. A round seed or a wrinkled seed, that's easy. Guess which one is dominant? The round seed is dominant. If you have the round seed allele, then you will express round seeds. You need two wrinkled seed alleles to express wrinkled seeds. Those are your possible phenotypes. The alleles, now I'm gonna tell you something else about this. The letters that you pick for your possible alleles are totally variable. There's nothing, in fact, unfortunately, we use different letters every time, so we have to define the letter that we're going to use to talk about a gene. It isn't like the S alleles match seed shape. It's that that was just what I made up or what I read somewhere or something, but you can have a dominant allele or a recessive allele. When I say possible genotypes, what are all the ways that we could combine those alleles in sets of two, right, because every genotype is gonna be diploid? Well, you could have a homozygous dominant genotype. You could have a heterozygous genotype or you could have, I want to change that. I'm making my S's like little cursive S's, which may be harder. I don't know, but S was a terrible choice because a lowercase S and a uppercase S look very similar. Two lowercase, you can have homozygous recessive genotypes. Now, watch this genotype. This one. My homozygous dominant genotype. What is the phenotype of the critter that's homozygous dominant? All you need is one big S allele and you will express the dominant phenotype. So both heterozygous and homozygous dominant express the round phenotype for seed shape. Holy cow. You following me, home kids? Let's see. The homozygous recessive genotype is corresponds with the wrinkled seed shape. So look at this situation. With our seed shape, we can have, if I tell you, this parent has wrinkled seeds. You go, okay, their phenotype is wrinkled. I know that they could have big S alleles or little S alleles, but they're wrinkled. That's the recessive phenotype, which means their genotype must be little S little S. If I told you I have a round seed shaped plant, you would say, oh, well that, I have two possible phenotypes. It could be homozygous dominant or heterozygous. And those two genotypes would express the round phenotype. How do you feel about this? The pattern is the same for all seven shapes. The only thing that I want to tell you is I'm going to go through and tell you the possible phenotypes and which one is dominant. So for our seed color, the color of the seed can be yellow or green. And I just will tell you that I did big Y and little Y for yellow seed color and yellow is dominant. Is that good enough for you? You can actually fill in all the other things. For pod shape, you can have, it says inflated, but I like puffy better. A puffy pod. A puffy pod is dominant. And then a crinkled, crinkled, it says constricted. That seems crinkled. A crinkled pod. But of course I put my alleles where I, big I and little I. Puffy. The puffy pod is dominant. Or pod colors. Oh goodness. Wait for this one. The pod color can be green or yellow. This is why I will not make you memorize any of this because the seed, the dominant seed color is yellow, but the dominant pod color is green. That's cool. But you can just refer to this. I made the alleles, big G and little G. You see what I'm doing here. Yes. Flower color, we can have purple or white. And again, purple is dominant. And I of course did big P and little P. Flower pod position. Let's see. We do in the stem or at the tip of, so the flowers at the tip of the plant or the flowers like in the armpit of the plant. And at the, in the armpit is dominant and at the tip is recessive. And I did F of course and little F, which makes total sense. But again, the letters are irrelevant. And I don't even know why I'm showing you the letters, except I really want to make sure you're comfortable with the fact that we match a phenotype to a genotype. We match the phenotype to the possible alleles or the genes, the, the forms of the genes for the trait we're looking at. Stem length, we can be tall, which is dominant, or we can be short, which is recessive. And of course we have big T and little T. Okay. You can go through and you can look at these different. We have round and wrinkled seeds. We have yellow and green seeds. We have tall and short plants. We have full and constricted puffy and squished pods. Like this visual helps you see the, the, what the characters actually look like traits, the form of the trait is the phenotype. The genes that code for the trait are the genotype. We basically have a puzzle now, and we can use this puzzle to figure out how Mendel, or we can figure out all sorts of problems. We're about to be armed with some really good tools for solving problems. But let's look at what Mendel did when he started making pee babies.