Understanding Non-Mendelian Genetics and Pedigrees

Well, good morning to everyone. Welcome into the Zoom. We have been, we started talking several days ago about Chapter 14. Is Andre the SI leader here? No. Okay. And good morning, Annika. And that film is usually in my second, yeah, in my second class. Okay, so we've been talking about now since Monday, non-Mendelian genetics. We're in Chapter 14. We talked about Mendelian genetics and all the definitions prior to that. So today, and again, what non-Mendelian means is the genes don't work the way Mendel envisioned them to work. Mendel said everybody gets two genes, one from each parent, and there's dominance and recessiveness. That's what Mendel figured out. And he was right, but there's just a lot more. So today we're going to see about a non-Mendelian topic. We talked about incomplete dominance last time. We're going to talk about multiple alleles today and co-dominance. and a lot of other ones. So multiple alleles means there's more than two genes for a trait. So in the ABO blood groups, you have to look at this on a population level. If we look at the population of our class, or the population of UCF, there is A and B and O alleles in various combinations. So in the population, there's more than two alleles. However, with the multiple allele system, every individual person or animal or whatever it is, plant, only gets two of the three alleles. So there are three genes, A, B, or O. in the blood group system, in the population, but every individual only gets two of the three genes in some combination. Good morning. There's Andrea. Okay. Andrea, is there anything you want to say to everybody? It's been a while. Good morning, everyone. Yes, my SI sessions are happening normally. Today I have one online from 6.30 to 7.20 p.m. on Zoom so you can attend. Next week I will have the exam review for your exam, your upcoming exam. I will let you know when I have the exact time that it will be happening. And this week my other sessions will be happening normally. Thank you. Okay, great. Um, yes. All right. So we're talking now about multiple alleles, where in a population, there's more than two genes for a trait, but individuals, in this case, only get two of the three genes. So A and B are dominant over O, okay? And I'm kind of going to show you why. We're going to kind of... draw a diagram. This is what A looks like. So on your blood cell, you have all these chemicals and the chemicals say A. Now it's not the letter A, but the chemicals say A. And if you're a B, the chemicals say B. This is on your blood cell. And if you're an O, the blood cell is bald. So there is an absence of A or B. So your blood cell doesn't have the chemical A or B marker if it's an O. So A and B are dominant over O. Okay. And then there's co-dominance. So this means a person that is blood type AB. equally expresses the A's and the B's. So an AB has the A's and the B's. That's what we call co-dominant. They each express equally. So for a minute, we're gonna, we talked about incomplete dominance one time before. So co-dominance would be this. Black cow plus white cow equals, if this is the cow, polka dots. Black, white. So this would be a polka dots. They both express evenly, equally. So in each retains its individual characteristic. So you have blood type AB, you have A and B. If the black cow meets with the white cow, and if this is co-dominant, you have spots. And you've seen those cows, actually. They have black spots and white spots. Okay, so that's co-dominance. But how does this contrast to incomplete dominance, which this is not, but incomplete dominance? would be black cow plus white cow equals gray cow. Just like we had red flower plus white flower equals pink flower in co-dominance in snapdragons, we said, and roses. Roses do all kinds of things. Carnations, poinsettias, in incomplete dominance. the genes like work it together and you get a third phenotype that's different. Here it's like they both equally express if they're co-dominant. Questions about that? That's kind of a lot. So A and B are co-dominant but if you have A O or B O, A is dominant over O because again if you have the A markers And then if you have an O marker, it's only going to show up as A. And B is also dominant over O. So A or B are dominant over O. And A and B are codominant, equally expressed with each other. And O is the super recessive. Okay, so in codominance, there's equal expression of... both traits individually and incomplete dominance like the two different traits kind of blend and you get a third phenotype that you've never seen before. Does that help? So here are Let's get this down here. Genotype, you can be AA. You're a type A. AO, there's O is bald, so you're a type A. BB, you're B. This is your blood type. BO, O is bald, so you're still a B. OO, all your cells are bald. AB, this is the codominant. A and B are both expressed. If this was... Incomplete dominance, it's not. This is not incomplete dominance. If this was incomplete dominance, you would have AB equals C, because C is a totally new phenotype in the F1. That's heterozygous. So, and here you see, we're not going to do antibodies and stuff. These are blood types. And then RH. RH is another factor. This is whether you're positive or negative. You know, A positive, A negative, B positive, B negative. This, we're going to treat this as Mendelian. So we're going to say there are two factors and there's dominance over recessive for this one. It's really not like that. It's super complicated. These are linked genes. called C.D.E. This is the fishery system. And they go together as a unit. And you can be like little c, big d, little e. You can be all these different combinations. You'll learn this part in Gen X. So it really is multiple genes, but we're not going to go there because it's way too complicated. So we're going to say if you're positive, you're positive. This works just like brown eyes and blue eyes. If you're positive with negative, the negative is recessive to the positive. Positive is dominant. You're still positive. Two negatives will give you a negative. So if you look at the A's and the B's and the O's and you look at dihybrid status, because you can be like A, O, positive, negative, like B, O, positive, positive. You can be all these different things. This is two different pairs. Here's one. pair that's heterozygous. Okay. Yes. So co-dominance, incomplete dominance, and multiple alleles are non-Mendelian. Yes. All of it is non-Mendelian. Mendel didn't say things work like this. Mendel was like, you get two, one from each parent, and they're strict, dominant, over-recessive. That was, he did good figuring it. it out but there's just a lot more. So we're going to talk about RH. RH in the past could be a problem. If the mother is RH negative and the baby is RH positive because if the baby got RH positive from its father and RH negative from its mother, usually during the first pregnancy you're okay. Okay. Once you deliver the baby, you know, the placenta comes loose and now the blood cells are mixing. The mother's body and her bloodstream and her white blood cells see the positive and think, aha, this is not me. I'm negative. And they make antibodies against positive. So it used to be that from the second pregnancy on, there were problems. The antibodies would be made by the mother. They would come across the placenta into the baby. They would lock. They are made against the baby's positive, Rh positive red blood cells, which are all of them, if the baby's Rh positive. And they literally start to lyse or take apart the baby's blood cells. This was a really big problem in the old days. When I was, you know, in the dinosaur age, when I was a student nurse, this was a really big problem. The babies would get anemic. They would sometimes, a lot of times, they would die and be stillborn. Or they would be born and we were trying to give them blood transfusions and they had organ damage and brain damage and it was a mess. They now have drugs that they can fix this with for 20 years already called well, the older generation was called Rogam. There are lots of different ones now. They literally will block the Rh negative mother from having an antibody response against the baby's blood cells. And it's very selective. It does not impair anything else in the mother's immune system. So it's very successful. And so in the old days, when I was a student nurse, all you prospective nurses out there, When you're a student, they give you really tough jobs to do to get you used to how it's going to be. As a student, my job, way back in the day, I had to go into the rooms of the mothers that were RH negative and had delivered their first baby, and I had to tell them that it was not recommended they had any other children. I went with a box of Kleenex. It was horrible. Now that doesn't happen anymore. because of all the advances, was the most, one of the most terrible jobs I ever did. The other most terrible job that I ever, thing I ever saw as a student nurse, well, I saw a lot of terrible things as a student nurse, but I worked in neonatal ICU with the wee tiny preemies, and there's just nothing worse than watching one of those little ones die. I mean, the parents have an expectation that They're going to spend their whole life with that child, and it's just devastating. So, you know, if you're going to be a nurse, you literally, you do, you actually start to think about, even as young as you are, like life and death and what do you think about that and how do you deal with this. And you literally figure out a construct for how you're going to manage all this. And you have to be able to clear your head by doing other things. You can't like dwell on it. They teach you a little bit of this, but a lot of how to do that head clearing stuff you learn on your own. when you're being a nurse or a doctor even. Let's look at an ABO problem. Okay. Yes. Okay. So we're going to do like a dihybrid ABO problem. Man is blood type A positive. Okay. That's great. But, you know, okay. We know he's A positive, but he's A something. He's either A, A, A, O, A, B, and he's positive. What's the rest of it? Let's keep, his father was O negative. The guy's A, O, positive, negative. It's not a double negative. That's just a negative. The man's wife is B, whatever, positive. Her mother was O negative. So this is the guy. This is his. significant other. Okay, now how many gametes are we going to make? Well this parent has two heterozygous pairs, two to the two, four from one parent, two to the two, four from the other parent, four times four, this is going to have 16 boxes. 16. Four gametes from each parent. That's a lot. And here it is. So let's, we had an A, O, positive, negative one parent. We had a B, O, positive, negative other. So we can get A with positive, A with negative, O with positive, O with negative. Next set, we can get B with positive, B with positive, B with negative. O with positive, O with negative. And again, the order that you have these in doesn't matter. If you put the O's first or the B's first or the B negative before the B positive, it's fine. You just have to have them all. 16 boxes. What's the probability of an O negative child that's totally recessive? 1 out of 16. The 2 to the n rule. The two to the n rule is involving the number of heterozygous pairs. So this, if it was, if it, we really have this. What if we had AO negative negative? Here we have one heterozygous pair, two heterozygous pairs. Two to the two, this person's going to make four kinds of gametes. What if it was AO negative negative? We have one heterozygous pair. That's a homozygous pair. That doesn't count. Two to the one. That one would make two. And then if we had like A, A, negative, negative, that's no heterozygous pairs. Two to the zero make one kind of gamete. They'll all be A negative. Questions, confusions, problems? It helps you to make sure that you're not making too many gametes for one parent. And then it gets you the number of boxes. So if we said, what are the AB, see here's like the sum rule. So if we say, what are the AB positive children? Like they could be positive with negative or they could be positive with positive. There's two out of 16, which is one eighth. Those three. Well, there's another one. I was going to say that's not right because I know genetics in my head. There's three. That's right. There should be 9, 3, 3, 1. Yep. Okay. All right. Questions. So these become dihybrid crosses. Now, what if we say... We saw the probability of an O-child is 1 out of 16. What if we add something and say, what is the chance of O negative and female embryo? That would be 1 16th for O negative times 1 half, because that's a separate probability for whatever embryonic gender, 1 out of 32. That's the multiplication rule of probability that we talked about. Okay, go back to, okay, this question. Somebody should show the question again. Is that what you mean? So again, in SI, in SARC, in... Office hours, which I'll have office hours today from 3 to 4. And your TAs are having office hours all the time, all week long at various times, various ones. And Andrea is having her SI sessions. This is where you can practice this. There's also a tremendous amount of practice up in web courses. There are free problem sheets with answers. There's a free practice quiz. Okay, now we're going to go to another kind of non-Mendelian inheritance called pleiotropy. Pleiotropy. This is when one gene can have many effects. Mendel said one gene does one thing. You know, you got eye color, you got hair color. Pleiotropy, one gene has a lot of effects. The sickle cell gene. As an example of this, it has a lot of effects. If the cell is sickle, then you can get anemic. You can have problems with oxygen concentrations. This gene affects susceptibility to malaria. If you are a carrier of sickle cell, you are resistant to malaria. And if you have sickle cell, you are resistant to malaria. So there are a lot of things that come with pleiotropies. Here's another example of pleiotropy. Chickens, usually you don't see him look like this. He looks like he didn't comb his feathers. This is called frizzled in chicken. And these genes are pleiotropic. Farmers that... have egg farms do not want frizzled chickens because they lay less eggs. That's one of the pleiotropies or other effects. They have these defective upturned feathers. That's the main part of the gene. Their body temperature and metabolic rate is higher, so they have to eat more. Farmers don't want that. Their blood flow is more rapid and they lay less eggs. Everything you wouldn't want if you're an egg farmer. So they don't like these. They don't want these and you don't see these. You know, people that are, you know, want rare chickens, okay, they'll have them maybe as a little pet or something, but that's about all. Epistasis, another non-Mendelian thing. Epistasis is where there's more than one gene involved in a pathway. for something and one gene interferes with the function of the other. One gene interferes or stops the function of the other. We call it masking. An example and this is I know really complicated so I don't want you to panic. An example of this is coat color in Labradors. Labrador Retrievers. So if you have at least one capital B, so in this pathway, we're going to call the genes B and E, but we'll show you in a minute what they really are. Coat color, you have to have the B for black. You also have to have the E because it's like a pathway. So like you make the E thing, then there's another enzyme you have to make. the B thing, you know, and you can make them either way. But usually you make the B first and then the E. And then you get like the black color. So when we have B blank, E blank, we mean you could have two big B's and two big E's, or you could have a big B, little B, big E, big E, or you could have, you know, any combination. You have to have at least one big B and one big E, and I don't want you to panic about this, to get black. Now, if you don't, if you have recessive little B's with a big E, you get chocolate labs. If you have one big B and little e's, this is the part that we call masking. It doesn't work. So these little e's, we call them amorphs, which I don't want you to freak out. It means they literally don't do their job. So as where when it's an e, it puts a part of the color together. The little e's are like recessive and they're like, nope, talk to the hand. We're not doing anything. So You make the B part and then you don't make the rest of it. And because the B part alone isn't finished, you get these golden labs, yellowish, goldenish. This is apestasis. One gene is interfering the little E genes. If you have little E genes, you're not getting brown or black no matter what else is there. Two golden doodle shoesies. Yeah, so yes, golden doodles have little e-jeans. And they have some other genes because of the doodle from the poodle. The doodle from the poodle. I have friends that have doodles. Okay, all right. Again. Are we going to ask you what's B and what's E? No. We're going to progress so that you can see what. So to show you what's really happening, there's these two genes involved. And the first gene is for a protein called TRP1. This is found in pigment storing organelles, which we didn't talk to you about during the organelle section. Okay. The second gene. You see in humans too, melanocortin-1 receptor, MC1R. In humans, MC1R is related to freckles. And so the TURP genes are like pigment storage. And then the MC1R genes are for pigment expression. These are the E's. So if you have little E's, you're not going to express the pigment no matter what's there. So yellow labs are either this or this. And again, you don't have to memorize this, but just so you can see, this is pleiotropy. One gene is affecting the other. Like you can have the gene for blood, but it's not going anywhere with these little E's because it nukes the rest of the pathway. We see this a lot in humans. Here's one more look. The M1CR gene, this is Pippi Longstocking. Stocking is associated with freckles in humans and red hair sometimes too. But freckles definitely. And it's not like it's a freckling gene. It's one of the components. This is also like a very complicated system. Okay. Freckles is really complicated. So if it causes freckles, but many people with red hair have MC1R. Okay. So again, you know, my parents, I was born to older parents and my parents were both unfortunately had died by the time I got to graduate school. And I They were trying to tell me that freckles were dominant and recessive and I have freckles and my parents didn't. And I was like, no, I know because I have my birth certificate that these are my parents. And that's when I knew there was more. And there so there's actually four genes that we know of right now. This is what we call polygenic. And we're going to talk when there's so many genes involved, like makes your head spin all over the genome of humans. MC1R, BNC2, OCA. A2 is an eye color gene too. And therefore, we know it's very complicated freckling. So if your parents don't have freckles and you do, or if they do and you don't, that's perfectly fine. Okay, we don't understand this all yet. Polygenic inheritance. This is when a single trait is influenced by so many genes. It's more genes than A and B and O. That's multiple alleles. It's like it can be hundreds of genes. And a lot of times we don't know them all yet. Currently, 150 genes have been found that influence. eye color, skin color, and hair color, and we're still going. We don't understand this all. Eye color is not what they told you about in high school. Now, we are going to do it on the test like Big B, Little B, because we don't want you to run away, but eye color is polygenic. It's so complicated that we don't still understand it all. We have a little bit of it. Um, the main gene is this OCA. two located on chromosome 15. There are eight more. OCA2 controls the blue-brown range, like the base colors. And then there's all these other, this is an example of naturally occurring violet eyes. Okay. They can occur in albinos or in any individual as a variation of blue. What this is, is you can see the blue and then the blood vessels being red behind it. Blue plus red makes purple. Okay. At any given time, there are only about 600 people in the world living that have violet eyes and sometimes less. It's a very, very rare coloration. There are things that have to happen to the blue gene. And there are all these modifiers. This is really interesting, too. So. This is the iris of your eye. This demarcation line, not everybody has such a very strong demarcation line. This is another kind of trait. And then all the flecks, you know, some people have like gold and stuff in their brown eyes. That's another set of genes. And we don't understand this all yet. But the real ones are really pretty. The contact lens ones are a little bit weird looking sometimes. Okay, so we have talked about non-Mendelian inheritance, things that are not inherited in the normal way that Mendel described. Questions about those examples? Okay, let's see one. RH, yes. Let's go back to RH for me. So RH, we're going to say it is Mendelian because otherwise it's, you know, it's like 3000 level genetics with their pregnancies. Okay, yes. So let's do this. So, you know, this, again, this applies, what we're saying now applies to the olden days. Even though now we can stop this from happening pretty much. Okay. So if the mother was negative, her blood cells are bald for RH. There's nothing there. Her white blood cells don't think that RH positive is like something that we need to kill because they think it's a germ. They think it's they're like, wait a minute, this is not me. And you will attack anything that's not you. So during the first pregnancy, normally you're okay. Sometimes not, but normally. Because everything's contained until delivery. Then delivery comes, placenta comes loose. All of the baby's Rh positives, you know, are mixed in with the mother's Rh negatives. Your white blood cells see it and say, wait a minute, this is a foreign object. And I, I am going to... kill it. And to kill it, there are certain things I'm going to do. And the first thing you do is you make antibodies. So these are antibodies against Rh positive. So you get pregnant the second time, the antibodies are ready. And it's a memory response, your antibody responses and gets this is why if you have allergies, they get worse and worse and worse. If you're exposed more, every time you make more and more antibodies. So in the second pregnancy in the old days, if the baby was messed up, but it lived and we got it through all that. If you went to have a third baby, that baby was probably going to be stillborn. And a lot of times the second baby was stillborn. They come across the placenta and attack the blood cells of the baby and lyse them. They break them apart. Now, breaking apart baby's blood cells is bad in two ways. The first way is the baby needs blood cells for oxygen. Second way is when you break apart blood cells, you release this stuff called bilirubin. Bilirubin, if it concentrates in high amounts in the baby's blood, will cause brain damage. So this is like a double win. Okay. I don't know if you guys have ever had friends. So babies and baby's blood, fetal hemoglobin is not the same as the mom's. Yeah, I mean, they're all human. Okay. But... You know, think about it. There has to be this, there's this incredible dance going on when people are pregnant between the baby has to take oxygen, but leave some for the mother. So the baby's hemoglobin, fetal hemoglobin is a different type than the mother's. When the baby's born, within a little bit, the baby starts slowly breaking up its hemoglobin and replacing it with adult hemoglobin even though it's a baby because now it's out in room oxygen and it's not connected to the mother anymore so it needs to be more efficient about getting oxygen. Sometimes when this happens the baby gets yellow you'll hear about jaundice that's turning yellow jaundice of the newborn this is when a baby is breaking up its blood cells to try to replace its blood cells with the adult hemoglobin a little bit too fast. You don't want that to get out of hand because of this Billy Rubin stuff. That's where you see the jaundice and everything because that can cause brain damage. So they have everything now. So if the baby is having a problem with that in the nursery, in the hospital, they have like little TV, kind of like swimsuit diapers. And they put little UV goggles on the baby. And it's like they put them under UV lights in an incubator. And it's like being at the beach. And they turn, turn, turn. And basically that UV is breaking up the bilirubin so they don't get jaundiced to a point where there's a problem. When they're ready to go home, if they still have that happening, they give the baby like a zoot suit. It's a little suit they put on. You zip them in. there's all these paddings so the lights don't hurt anything. There are like LED UV lights in there. So you can go to the grocery store and your baby has a suit on and it's actually really pretty cool what they can do now. Like roasting a chicken. Yeah. Yeah. Only, you know, they don't let the lights get hot or anything. So like rotisserie chicken. Yeah. So other questions. So yeah, there's all kinds of stuff that they do. But back in the day in the dinosaur age when I was a student nurse, we didn't have all those options. And so we were biting our nails a lot and hoping. Okay, so we're going to start to talk about pedigrees. I doubt that we're going to get through all this today, which is fine. Some basic symbols. Pedigrees. And you've seen them before. There are these big things that this is generations. Usually it says one, two, three. The generations, it can say A, B, C, but it usually says one, two, three. Pedigrees are these organized way to look generationally through the generations to see, do we see a trend on what is going on? How is being inherited? What are the genotypes of the parents? those kinds of things. Now in real life, geneticists use computers, modified Markov chains, all you computer scientists. We use computers to do this stuff. We have to weight with things called LOD scores. We like do weighting of things. It's a lot more complicated than they taught you if they taught you in high school. We're going to do some basic ones. This is some of the most interesting stuff. Circle is a female, square is a male. Colored in can be affected or you have to be careful because some problems say the colored in are not affected. So you have to read the problem. A line through it means that this is twins and we're going to talk about there's different kinds of twins, right? There's fraternal twins where they're not identical. And there's identical twins where they are identical. So there's going to be more symbols for this adopted and miscarriage. Okay, this means, you know, had kids together, married significant other, whatever. This means These are going to be the children of these people. These are the siblings. This is brother and sister here. Generation one, generation two. Okay, so let's look a little bit at this. I can never find a good place to put these. That's not good. I'll just put it here for the moment. So they let us determine transmission of traits in families. Okay. So here we're looking at earlobes and again this has absolutely no significance in life. Some of these traits are just there. They're what we call neutral. It doesn't matter what kind of earlobes you have. They can be attached so you don't have more fleshy part there. That's recessive or they can be the more floppy fleshy kind. That's dominant. So here we see the recessive, obviously because they had children that are recessive, this one was a carrier. So these are pedigrees. What are, again, some of the ways traits are inherited we've talked about. There are autosomal recessive disorders like blue eyes or, you know, not disorders, syndromes or traits. And then there are diseases that are cystic fibrosis is recessive. You get two little C's, one from each parent. The people can't breathe right. They have problems. They have lung infections. It's your chloride channels in your lung cell, CO minus channel, transporter channels. That's what it is. There are 508 different mutations. that get you to cystic fibrosis. 508 different ways for the chloride channel to go wrong. And when we get to Chapter 17, we'll talk more about things. Tay-Sachs disease. We talked about Tay-Sachs a long time ago. We said this is neurological degeneration in the worst-case scenario. Two little Ts. But interesting. On both of these cystic fibrosis and Tay-Sachs, genetically, they're totally recessive. But if you run a protein gel where you get the protein that they make, you can see if people are carriers or not by what happens in the lanes as the gels run. It's very interesting on a protein level. Sickle cell, same as... SpaceX. It's recessive, autosomal recessive. So there are many, many of these things, but here's three examples of something that's in a pedigree that would go by being autosomal recessive. Some of the autosomal dominance, Huntington's disease. This is the neurological degeneration between the ages of 35 and 50. And we're going to find out that I'm partly lying about Huntington's. Huntington's is a... as a molecular disease. But we're not there yet for me to explain it to you. I will explain it to you in chapter 16 and 17. Echondroplasia is what you guys call dwarfism, super short stature. There are many different kinds of that. Some of it is dominant. Some of it is recessive. Most of it is dominant. Neurofibromatosis is where people get like benign tumors all over their skin. These are dominant disorders, and there are so many of these. You know, again, some other traits. Here's widow's peak that we talked about. Here coming to us, this is a neutral trait. It doesn't mean anything. And here in cats, manx, which is the short tail, and munchkin, which is the super short legs. Now, this is an autosomal dominant that is lethal. in the homozygous dominant condition both of them so if you have manx manx those kittens aren't going to live. You're never going to see them. That box is gone. If you have munchkin munchkin, that box in your punnett square is gone. And so let's do this for a minute. These cats also, this cat's very fortunate. Here when manx happens, sometimes it's more severe and like this, they don't have a nub at all. And if they don't have a nub, it can affect their spine. And the innervation for their bowels and bladder are right there. And so some of these Manx cats that don't have the tail joint have to wear little diapers. And it can affect their legs sometimes. But usually it's bowel and bladder function. This one is fine. He's got a joint there. These cats, the munchkins they have, Some intestinal problems and stuff, I can relate to that. My cat has intestinal problems, but is not a munchkin. They can jump normally and everything. They're cute little buggers, but it's not normal. These are mutations that arose spontaneously. So let's say we have a munchkin. We know if the munchkin parent is alive, they have to be a big M, big M. In munchkin, big M, big M. dies as an embryo. So you don't even see these in the world. So if it's two munchkin parents, they both have to be big M, little m, and then you get big M, little m. If it's two munchkins, oh that's not good, let me get it, there you go, little m. So you get this dies, that box is gone. So you have two-thirds munchkin to one-third normal. Now, what if, I'm just going to do this in white, what if we have a munchkin parent with a normal? So they're not munchkin, they have normal legs. Okay, let me do this in pink. Then you're not going to have a problem where you lose boxes because you don't have two big M's. And then again, one kind is represented one time. You don't have to keep writing those little ones. So you would have 50% munchkin, 50% regular legs, and you couldn't get any that are dead because you don't have the other big end. Same thing with mink, same exact thing. Questions about this? do it on time so rules about pedigrees if somebody marries into the family and we're going to see this and you you don't know any information about them so like it would be kind of like this it was a mother and a father and let's say they had a son okay that's not a square there you go and you The son marries some lady. Okay, we know nothing about her. If we know nothing about her, we presume she's genotypically normal at this point in time. Again, when you get into advanced genetics and 3063, they'll teach you different ways to handle this by probability. Okay, genotypically normal means So let's say this is a key for cystic fibrosis. Cystic fibrosis is autosomal recessive. This is a carrier. They don't have cystic fibrosis, but they can pass the genome. This is genotypically normal, perfect genes. Now we said if the trait is dominant, then that's different. So if this is dwarfism. So this is short stature. And this is short stature. And this is tall, regular. And now here, the situation was on the recessives. So it's the opposite. The total homozygous dominance are genitive and gluemul. here It's the dominance that have the problem. So genotypically normal is the opposite, which is the homozygous recessive. Just about all the time. Let's do that. Okay. Questions about this stuff? So we're going to start next time looking at the pedigrees, and we're good. We still have plenty of time, even though it says we were going to be done with pedigrees today. We are not going to be done with pedigrees today. We'll be done with pedigrees next time, and then we'll keep going into Chapter 15. Any questions about any of these things?

Well, good morning to everyone. Welcome into the Zoom. We have been, we started talking several days ago about Chapter 14. Is Andre the SI leader here? No.

Okay. And good morning, Annika. And that film is usually in my second, yeah, in my second class. Okay, so we've been talking about now since Monday, non-Mendelian genetics. We're in Chapter 14. We talked about Mendelian genetics and all the definitions prior to that.

So today, and again, what non-Mendelian means is the genes don't work the way Mendel envisioned them to work. Mendel said everybody gets two genes, one from each parent, and there's dominance and recessiveness. That's what Mendel figured out. And he was right, but there's just a lot more. So today we're going to see about a non-Mendelian topic.

We talked about incomplete dominance last time. We're going to talk about multiple alleles today and co-dominance. and a lot of other ones. So multiple alleles means there's more than two genes for a trait.

So in the ABO blood groups, you have to look at this on a population level. If we look at the population of our class, or the population of UCF, there is A and B and O alleles in various combinations. So in the population, there's more than two alleles.

However, with the multiple allele system, every individual person or animal or whatever it is, plant, only gets two of the three alleles. So there are three genes, A, B, or O. in the blood group system, in the population, but every individual only gets two of the three genes in some combination. Good morning. There's Andrea.

Okay. Andrea, is there anything you want to say to everybody? It's been a while.

Good morning, everyone. Yes, my SI sessions are happening normally. Today I have one online from 6.30 to 7.20 p.m. on Zoom so you can attend. Next week I will have the exam review for your exam, your upcoming exam.

I will let you know when I have the exact time that it will be happening. And this week my other sessions will be happening normally. Thank you. Okay, great. Um, yes.

All right. So we're talking now about multiple alleles, where in a population, there's more than two genes for a trait, but individuals, in this case, only get two of the three genes. So A and B are dominant over O, okay?

And I'm kind of going to show you why. We're going to kind of... draw a diagram.

This is what A looks like. So on your blood cell, you have all these chemicals and the chemicals say A. Now it's not the letter A, but the chemicals say A.

And if you're a B, the chemicals say B. This is on your blood cell. And if you're an O, the blood cell is bald. So there is an absence of A or B.

So your blood cell doesn't have the chemical A or B marker if it's an O. So A and B are dominant over O. Okay.

And then there's co-dominance. So this means a person that is blood type AB. equally expresses the A's and the B's. So an AB has the A's and the B's.

That's what we call co-dominant. They each express equally. So for a minute, we're gonna, we talked about incomplete dominance one time before.

So co-dominance would be this. Black cow plus white cow equals, if this is the cow, polka dots. Black, white.

So this would be a polka dots. They both express evenly, equally. So in each retains its individual characteristic. So you have blood type AB, you have A and B. If the black cow meets with the white cow, and if this is co-dominant, you have spots.

And you've seen those cows, actually. They have black spots and white spots. Okay, so that's co-dominance. But how does this contrast to incomplete dominance, which this is not, but incomplete dominance?

would be black cow plus white cow equals gray cow. Just like we had red flower plus white flower equals pink flower in co-dominance in snapdragons, we said, and roses. Roses do all kinds of things. Carnations, poinsettias, in incomplete dominance.

the genes like work it together and you get a third phenotype that's different. Here it's like they both equally express if they're co-dominant. Questions about that? That's kind of a lot.

So A and B are co-dominant but if you have A O or B O, A is dominant over O because again if you have the A markers And then if you have an O marker, it's only going to show up as A. And B is also dominant over O. So A or B are dominant over O. And A and B are codominant, equally expressed with each other. And O is the super recessive.

Okay, so in codominance, there's equal expression of... both traits individually and incomplete dominance like the two different traits kind of blend and you get a third phenotype that you've never seen before. Does that help?

So here are Let's get this down here. Genotype, you can be AA. You're a type A.

AO, there's O is bald, so you're a type A. BB, you're B. This is your blood type.

BO, O is bald, so you're still a B. OO, all your cells are bald. AB, this is the codominant.

A and B are both expressed. If this was... Incomplete dominance, it's not. This is not incomplete dominance. If this was incomplete dominance, you would have AB equals C, because C is a totally new phenotype in the F1.

That's heterozygous. So, and here you see, we're not going to do antibodies and stuff. These are blood types.

And then RH. RH is another factor. This is whether you're positive or negative.

You know, A positive, A negative, B positive, B negative. This, we're going to treat this as Mendelian. So we're going to say there are two factors and there's dominance over recessive for this one.

It's really not like that. It's super complicated. These are linked genes.

called C.D.E. This is the fishery system. And they go together as a unit. And you can be like little c, big d, little e. You can be all these different combinations.

You'll learn this part in Gen X. So it really is multiple genes, but we're not going to go there because it's way too complicated. So we're going to say if you're positive, you're positive. This works just like brown eyes and blue eyes. If you're positive with negative, the negative is recessive to the positive. Positive is dominant.

You're still positive. Two negatives will give you a negative. So if you look at the A's and the B's and the O's and you look at dihybrid status, because you can be like A, O, positive, negative, like B, O, positive, positive. You can be all these different things. This is two different pairs.

Here's one. pair that's heterozygous. Okay. Yes. So co-dominance, incomplete dominance, and multiple alleles are non-Mendelian.

Yes. All of it is non-Mendelian. Mendel didn't say things work like this.

Mendel was like, you get two, one from each parent, and they're strict, dominant, over-recessive. That was, he did good figuring it. it out but there's just a lot more. So we're going to talk about RH. RH in the past could be a problem.

If the mother is RH negative and the baby is RH positive because if the baby got RH positive from its father and RH negative from its mother, usually during the first pregnancy you're okay. Okay. Once you deliver the baby, you know, the placenta comes loose and now the blood cells are mixing.

The mother's body and her bloodstream and her white blood cells see the positive and think, aha, this is not me. I'm negative. And they make antibodies against positive. So it used to be that from the second pregnancy on, there were problems. The antibodies would be made by the mother.

They would come across the placenta into the baby. They would lock. They are made against the baby's positive, Rh positive red blood cells, which are all of them, if the baby's Rh positive.

And they literally start to lyse or take apart the baby's blood cells. This was a really big problem in the old days. When I was, you know, in the dinosaur age, when I was a student nurse, this was a really big problem.

The babies would get anemic. They would sometimes, a lot of times, they would die and be stillborn. Or they would be born and we were trying to give them blood transfusions and they had organ damage and brain damage and it was a mess. They now have drugs that they can fix this with for 20 years already called well, the older generation was called Rogam.

There are lots of different ones now. They literally will block the Rh negative mother from having an antibody response against the baby's blood cells. And it's very selective. It does not impair anything else in the mother's immune system.

So it's very successful. And so in the old days, when I was a student nurse, all you prospective nurses out there, When you're a student, they give you really tough jobs to do to get you used to how it's going to be. As a student, my job, way back in the day, I had to go into the rooms of the mothers that were RH negative and had delivered their first baby, and I had to tell them that it was not recommended they had any other children.

I went with a box of Kleenex. It was horrible. Now that doesn't happen anymore.

because of all the advances, was the most, one of the most terrible jobs I ever did. The other most terrible job that I ever, thing I ever saw as a student nurse, well, I saw a lot of terrible things as a student nurse, but I worked in neonatal ICU with the wee tiny preemies, and there's just nothing worse than watching one of those little ones die. I mean, the parents have an expectation that They're going to spend their whole life with that child, and it's just devastating. So, you know, if you're going to be a nurse, you literally, you do, you actually start to think about, even as young as you are, like life and death and what do you think about that and how do you deal with this.

And you literally figure out a construct for how you're going to manage all this. And you have to be able to clear your head by doing other things. You can't like dwell on it.

They teach you a little bit of this, but a lot of how to do that head clearing stuff you learn on your own. when you're being a nurse or a doctor even. Let's look at an ABO problem. Okay.

Yes. Okay. So we're going to do like a dihybrid ABO problem.

Man is blood type A positive. Okay. That's great. But, you know, okay. We know he's A positive, but he's A something.

He's either A, A, A, O, A, B, and he's positive. What's the rest of it? Let's keep, his father was O negative. The guy's A, O, positive, negative. It's not a double negative.

That's just a negative. The man's wife is B, whatever, positive. Her mother was O negative.

So this is the guy. This is his. significant other.

Okay, now how many gametes are we going to make? Well this parent has two heterozygous pairs, two to the two, four from one parent, two to the two, four from the other parent, four times four, this is going to have 16 boxes. 16. Four gametes from each parent. That's a lot. And here it is.

So let's, we had an A, O, positive, negative one parent. We had a B, O, positive, negative other. So we can get A with positive, A with negative, O with positive, O with negative. Next set, we can get B with positive, B with positive, B with negative. O with positive, O with negative.

And again, the order that you have these in doesn't matter. If you put the O's first or the B's first or the B negative before the B positive, it's fine. You just have to have them all. 16 boxes.

What's the probability of an O negative child that's totally recessive? 1 out of 16. The 2 to the n rule. The two to the n rule is involving the number of heterozygous pairs. So this, if it was, if it, we really have this.

What if we had AO negative negative? Here we have one heterozygous pair, two heterozygous pairs. Two to the two, this person's going to make four kinds of gametes. What if it was AO negative negative? We have one heterozygous pair.

That's a homozygous pair. That doesn't count. Two to the one.

That one would make two. And then if we had like A, A, negative, negative, that's no heterozygous pairs. Two to the zero make one kind of gamete.

They'll all be A negative. Questions, confusions, problems? It helps you to make sure that you're not making too many gametes for one parent.

And then it gets you the number of boxes. So if we said, what are the AB, see here's like the sum rule. So if we say, what are the AB positive children?

Like they could be positive with negative or they could be positive with positive. There's two out of 16, which is one eighth. Those three.

Well, there's another one. I was going to say that's not right because I know genetics in my head. There's three. That's right. There should be 9, 3, 3, 1. Yep.

Okay. All right. Questions. So these become dihybrid crosses. Now, what if we say...

We saw the probability of an O-child is 1 out of 16. What if we add something and say, what is the chance of O negative and female embryo? That would be 1 16th for O negative times 1 half, because that's a separate probability for whatever embryonic gender, 1 out of 32. That's the multiplication rule of probability that we talked about. Okay, go back to, okay, this question.

Somebody should show the question again. Is that what you mean? So again, in SI, in SARC, in... Office hours, which I'll have office hours today from 3 to 4. And your TAs are having office hours all the time, all week long at various times, various ones.

And Andrea is having her SI sessions. This is where you can practice this. There's also a tremendous amount of practice up in web courses.

There are free problem sheets with answers. There's a free practice quiz. Okay, now we're going to go to another kind of non-Mendelian inheritance called pleiotropy.

Pleiotropy. This is when one gene can have many effects. Mendel said one gene does one thing.

You know, you got eye color, you got hair color. Pleiotropy, one gene has a lot of effects. The sickle cell gene.

As an example of this, it has a lot of effects. If the cell is sickle, then you can get anemic. You can have problems with oxygen concentrations.

This gene affects susceptibility to malaria. If you are a carrier of sickle cell, you are resistant to malaria. And if you have sickle cell, you are resistant to malaria.

So there are a lot of things that come with pleiotropies. Here's another example of pleiotropy. Chickens, usually you don't see him look like this. He looks like he didn't comb his feathers. This is called frizzled in chicken.

And these genes are pleiotropic. Farmers that... have egg farms do not want frizzled chickens because they lay less eggs.

That's one of the pleiotropies or other effects. They have these defective upturned feathers. That's the main part of the gene. Their body temperature and metabolic rate is higher, so they have to eat more.

Farmers don't want that. Their blood flow is more rapid and they lay less eggs. Everything you wouldn't want if you're an egg farmer. So they don't like these.

They don't want these and you don't see these. You know, people that are, you know, want rare chickens, okay, they'll have them maybe as a little pet or something, but that's about all. Epistasis, another non-Mendelian thing.

Epistasis is where there's more than one gene involved in a pathway. for something and one gene interferes with the function of the other. One gene interferes or stops the function of the other. We call it masking. An example and this is I know really complicated so I don't want you to panic.

An example of this is coat color in Labradors. Labrador Retrievers. So if you have at least one capital B, so in this pathway, we're going to call the genes B and E, but we'll show you in a minute what they really are.

Coat color, you have to have the B for black. You also have to have the E because it's like a pathway. So like you make the E thing, then there's another enzyme you have to make.

the B thing, you know, and you can make them either way. But usually you make the B first and then the E. And then you get like the black color. So when we have B blank, E blank, we mean you could have two big B's and two big E's, or you could have a big B, little B, big E, big E, or you could have, you know, any combination.

You have to have at least one big B and one big E, and I don't want you to panic about this, to get black. Now, if you don't, if you have recessive little B's with a big E, you get chocolate labs. If you have one big B and little e's, this is the part that we call masking. It doesn't work. So these little e's, we call them amorphs, which I don't want you to freak out.

It means they literally don't do their job. So as where when it's an e, it puts a part of the color together. The little e's are like recessive and they're like, nope, talk to the hand. We're not doing anything. So You make the B part and then you don't make the rest of it.

And because the B part alone isn't finished, you get these golden labs, yellowish, goldenish. This is apestasis. One gene is interfering the little E genes.

If you have little E genes, you're not getting brown or black no matter what else is there. Two golden doodle shoesies. Yeah, so yes, golden doodles have little e-jeans.

And they have some other genes because of the doodle from the poodle. The doodle from the poodle. I have friends that have doodles. Okay, all right.

Again. Are we going to ask you what's B and what's E? No. We're going to progress so that you can see what. So to show you what's really happening, there's these two genes involved.

And the first gene is for a protein called TRP1. This is found in pigment storing organelles, which we didn't talk to you about during the organelle section. Okay. The second gene.

You see in humans too, melanocortin-1 receptor, MC1R. In humans, MC1R is related to freckles. And so the TURP genes are like pigment storage. And then the MC1R genes are for pigment expression.

These are the E's. So if you have little E's, you're not going to express the pigment no matter what's there. So yellow labs are either this or this.

And again, you don't have to memorize this, but just so you can see, this is pleiotropy. One gene is affecting the other. Like you can have the gene for blood, but it's not going anywhere with these little E's because it nukes the rest of the pathway. We see this a lot in humans.

Here's one more look. The M1CR gene, this is Pippi Longstocking. Stocking is associated with freckles in humans and red hair sometimes too. But freckles definitely. And it's not like it's a freckling gene.

It's one of the components. This is also like a very complicated system. Okay.

Freckles is really complicated. So if it causes freckles, but many people with red hair have MC1R. Okay. So again, you know, my parents, I was born to older parents and my parents were both unfortunately had died by the time I got to graduate school.

And I They were trying to tell me that freckles were dominant and recessive and I have freckles and my parents didn't. And I was like, no, I know because I have my birth certificate that these are my parents. And that's when I knew there was more.

And there so there's actually four genes that we know of right now. This is what we call polygenic. And we're going to talk when there's so many genes involved, like makes your head spin all over the genome of humans. MC1R, BNC2, OCA. A2 is an eye color gene too.

And therefore, we know it's very complicated freckling. So if your parents don't have freckles and you do, or if they do and you don't, that's perfectly fine. Okay, we don't understand this all yet. Polygenic inheritance. This is when a single trait is influenced by so many genes.

It's more genes than A and B and O. That's multiple alleles. It's like it can be hundreds of genes.

And a lot of times we don't know them all yet. Currently, 150 genes have been found that influence. eye color, skin color, and hair color, and we're still going. We don't understand this all. Eye color is not what they told you about in high school.

Now, we are going to do it on the test like Big B, Little B, because we don't want you to run away, but eye color is polygenic. It's so complicated that we don't still understand it all. We have a little bit of it. Um, the main gene is this OCA. two located on chromosome 15. There are eight more.

OCA2 controls the blue-brown range, like the base colors. And then there's all these other, this is an example of naturally occurring violet eyes. Okay.

They can occur in albinos or in any individual as a variation of blue. What this is, is you can see the blue and then the blood vessels being red behind it. Blue plus red makes purple. Okay. At any given time, there are only about 600 people in the world living that have violet eyes and sometimes less.

It's a very, very rare coloration. There are things that have to happen to the blue gene. And there are all these modifiers. This is really interesting, too.

So. This is the iris of your eye. This demarcation line, not everybody has such a very strong demarcation line.

This is another kind of trait. And then all the flecks, you know, some people have like gold and stuff in their brown eyes. That's another set of genes.

And we don't understand this all yet. But the real ones are really pretty. The contact lens ones are a little bit weird looking sometimes.

Okay, so we have talked about non-Mendelian inheritance, things that are not inherited in the normal way that Mendel described. Questions about those examples? Okay, let's see one. RH, yes. Let's go back to RH for me.

So RH, we're going to say it is Mendelian because otherwise it's, you know, it's like 3000 level genetics with their pregnancies. Okay, yes. So let's do this. So, you know, this, again, this applies, what we're saying now applies to the olden days. Even though now we can stop this from happening pretty much.

Okay. So if the mother was negative, her blood cells are bald for RH. There's nothing there. Her white blood cells don't think that RH positive is like something that we need to kill because they think it's a germ.

They think it's they're like, wait a minute, this is not me. And you will attack anything that's not you. So during the first pregnancy, normally you're okay.

Sometimes not, but normally. Because everything's contained until delivery. Then delivery comes, placenta comes loose. All of the baby's Rh positives, you know, are mixed in with the mother's Rh negatives.

Your white blood cells see it and say, wait a minute, this is a foreign object. And I, I am going to... kill it.

And to kill it, there are certain things I'm going to do. And the first thing you do is you make antibodies. So these are antibodies against Rh positive.

So you get pregnant the second time, the antibodies are ready. And it's a memory response, your antibody responses and gets this is why if you have allergies, they get worse and worse and worse. If you're exposed more, every time you make more and more antibodies. So in the second pregnancy in the old days, if the baby was messed up, but it lived and we got it through all that.

If you went to have a third baby, that baby was probably going to be stillborn. And a lot of times the second baby was stillborn. They come across the placenta and attack the blood cells of the baby and lyse them. They break them apart.

Now, breaking apart baby's blood cells is bad in two ways. The first way is the baby needs blood cells for oxygen. Second way is when you break apart blood cells, you release this stuff called bilirubin.

Bilirubin, if it concentrates in high amounts in the baby's blood, will cause brain damage. So this is like a double win. Okay. I don't know if you guys have ever had friends.

So babies and baby's blood, fetal hemoglobin is not the same as the mom's. Yeah, I mean, they're all human. Okay.

But... You know, think about it. There has to be this, there's this incredible dance going on when people are pregnant between the baby has to take oxygen, but leave some for the mother.

So the baby's hemoglobin, fetal hemoglobin is a different type than the mother's. When the baby's born, within a little bit, the baby starts slowly breaking up its hemoglobin and replacing it with adult hemoglobin even though it's a baby because now it's out in room oxygen and it's not connected to the mother anymore so it needs to be more efficient about getting oxygen. Sometimes when this happens the baby gets yellow you'll hear about jaundice that's turning yellow jaundice of the newborn this is when a baby is breaking up its blood cells to try to replace its blood cells with the adult hemoglobin a little bit too fast.

You don't want that to get out of hand because of this Billy Rubin stuff. That's where you see the jaundice and everything because that can cause brain damage. So they have everything now. So if the baby is having a problem with that in the nursery, in the hospital, they have like little TV, kind of like swimsuit diapers. And they put little UV goggles on the baby.

And it's like they put them under UV lights in an incubator. And it's like being at the beach. And they turn, turn, turn.

And basically that UV is breaking up the bilirubin so they don't get jaundiced to a point where there's a problem. When they're ready to go home, if they still have that happening, they give the baby like a zoot suit. It's a little suit they put on.

You zip them in. there's all these paddings so the lights don't hurt anything. There are like LED UV lights in there.

So you can go to the grocery store and your baby has a suit on and it's actually really pretty cool what they can do now. Like roasting a chicken. Yeah.

Yeah. Only, you know, they don't let the lights get hot or anything. So like rotisserie chicken. Yeah.

So other questions. So yeah, there's all kinds of stuff that they do. But back in the day in the dinosaur age when I was a student nurse, we didn't have all those options. And so we were biting our nails a lot and hoping.

Okay, so we're going to start to talk about pedigrees. I doubt that we're going to get through all this today, which is fine. Some basic symbols.

Pedigrees. And you've seen them before. There are these big things that this is generations.

Usually it says one, two, three. The generations, it can say A, B, C, but it usually says one, two, three. Pedigrees are these organized way to look generationally through the generations to see, do we see a trend on what is going on?

How is being inherited? What are the genotypes of the parents? those kinds of things.

Now in real life, geneticists use computers, modified Markov chains, all you computer scientists. We use computers to do this stuff. We have to weight with things called LOD scores. We like do weighting of things. It's a lot more complicated than they taught you if they taught you in high school.

We're going to do some basic ones. This is some of the most interesting stuff. Circle is a female, square is a male. Colored in can be affected or you have to be careful because some problems say the colored in are not affected. So you have to read the problem.

A line through it means that this is twins and we're going to talk about there's different kinds of twins, right? There's fraternal twins where they're not identical. And there's identical twins where they are identical. So there's going to be more symbols for this adopted and miscarriage.

Okay, this means, you know, had kids together, married significant other, whatever. This means These are going to be the children of these people. These are the siblings. This is brother and sister here.

Generation one, generation two. Okay, so let's look a little bit at this. I can never find a good place to put these.

That's not good. I'll just put it here for the moment. So they let us determine transmission of traits in families. Okay.

So here we're looking at earlobes and again this has absolutely no significance in life. Some of these traits are just there. They're what we call neutral.

It doesn't matter what kind of earlobes you have. They can be attached so you don't have more fleshy part there. That's recessive or they can be the more floppy fleshy kind. That's dominant. So here we see the recessive, obviously because they had children that are recessive, this one was a carrier.

So these are pedigrees. What are, again, some of the ways traits are inherited we've talked about. There are autosomal recessive disorders like blue eyes or, you know, not disorders, syndromes or traits.

And then there are diseases that are cystic fibrosis is recessive. You get two little C's, one from each parent. The people can't breathe right.

They have problems. They have lung infections. It's your chloride channels in your lung cell, CO minus channel, transporter channels.

That's what it is. There are 508 different mutations. that get you to cystic fibrosis.

508 different ways for the chloride channel to go wrong. And when we get to Chapter 17, we'll talk more about things. Tay-Sachs disease. We talked about Tay-Sachs a long time ago.

We said this is neurological degeneration in the worst-case scenario. Two little Ts. But interesting.

On both of these cystic fibrosis and Tay-Sachs, genetically, they're totally recessive. But if you run a protein gel where you get the protein that they make, you can see if people are carriers or not by what happens in the lanes as the gels run. It's very interesting on a protein level.

Sickle cell, same as... SpaceX. It's recessive, autosomal recessive.

So there are many, many of these things, but here's three examples of something that's in a pedigree that would go by being autosomal recessive. Some of the autosomal dominance, Huntington's disease. This is the neurological degeneration between the ages of 35 and 50. And we're going to find out that I'm partly lying about Huntington's.

Huntington's is a... as a molecular disease. But we're not there yet for me to explain it to you.

I will explain it to you in chapter 16 and 17. Echondroplasia is what you guys call dwarfism, super short stature. There are many different kinds of that. Some of it is dominant.

Some of it is recessive. Most of it is dominant. Neurofibromatosis is where people get like benign tumors all over their skin.

These are dominant disorders, and there are so many of these. You know, again, some other traits. Here's widow's peak that we talked about. Here coming to us, this is a neutral trait.

It doesn't mean anything. And here in cats, manx, which is the short tail, and munchkin, which is the super short legs. Now, this is an autosomal dominant that is lethal. in the homozygous dominant condition both of them so if you have manx manx those kittens aren't going to live. You're never going to see them.

That box is gone. If you have munchkin munchkin, that box in your punnett square is gone. And so let's do this for a minute. These cats also, this cat's very fortunate. Here when manx happens, sometimes it's more severe and like this, they don't have a nub at all.

And if they don't have a nub, it can affect their spine. And the innervation for their bowels and bladder are right there. And so some of these Manx cats that don't have the tail joint have to wear little diapers. And it can affect their legs sometimes.

But usually it's bowel and bladder function. This one is fine. He's got a joint there. These cats, the munchkins they have, Some intestinal problems and stuff, I can relate to that.

My cat has intestinal problems, but is not a munchkin. They can jump normally and everything. They're cute little buggers, but it's not normal. These are mutations that arose spontaneously.

So let's say we have a munchkin. We know if the munchkin parent is alive, they have to be a big M, big M. In munchkin, big M, big M.

dies as an embryo. So you don't even see these in the world. So if it's two munchkin parents, they both have to be big M, little m, and then you get big M, little m. If it's two munchkins, oh that's not good, let me get it, there you go, little m. So you get this dies, that box is gone.

So you have two-thirds munchkin to one-third normal. Now, what if, I'm just going to do this in white, what if we have a munchkin parent with a normal? So they're not munchkin, they have normal legs. Okay, let me do this in pink.

Then you're not going to have a problem where you lose boxes because you don't have two big M's. And then again, one kind is represented one time. You don't have to keep writing those little ones.

So you would have 50% munchkin, 50% regular legs, and you couldn't get any that are dead because you don't have the other big end. Same thing with mink, same exact thing. Questions about this?

do it on time so rules about pedigrees if somebody marries into the family and we're going to see this and you you don't know any information about them so like it would be kind of like this it was a mother and a father and let's say they had a son okay that's not a square there you go and you The son marries some lady. Okay, we know nothing about her. If we know nothing about her, we presume she's genotypically normal at this point in time.

Again, when you get into advanced genetics and 3063, they'll teach you different ways to handle this by probability. Okay, genotypically normal means So let's say this is a key for cystic fibrosis. Cystic fibrosis is autosomal recessive.

This is a carrier. They don't have cystic fibrosis, but they can pass the genome. This is genotypically normal, perfect genes.

Now we said if the trait is dominant, then that's different. So if this is dwarfism. So this is short stature. And this is short stature. And this is tall, regular.

And now here, the situation was on the recessives. So it's the opposite. The total homozygous dominance are genitive and gluemul. here It's the dominance that have the problem.

So genotypically normal is the opposite, which is the homozygous recessive. Just about all the time. Let's do that. Okay.

Questions about this stuff? So we're going to start next time looking at the pedigrees, and we're good. We still have plenty of time, even though it says we were going to be done with pedigrees today.

We are not going to be done with pedigrees today. We'll be done with pedigrees next time, and then we'll keep going into Chapter 15. Any questions about any of these things?

Transcript for:Understanding Non-Mendelian Genetics and Pedigrees

Transcript for:
Understanding Non-Mendelian Genetics and Pedigrees