this lecture is going to be part two so if you have not watched part one on heredity and Punit squares and inheritance please make sure you watch that um because this is going to be where we do more advanced problems and also dive into some more concepts related to in inheritance and heredity okay so what we've covered before in which we had um something like let's say um Talk talking about if something is red versus if it's white and you have a heterozygous um item that is red that is going to be complete dominance right that dominant Al is going to completely cover that little recessive Al however we have some cases in which there is something called incomplete dominance incomplete dominance and this incomplete dominance is going to give us a mixed phenotype so anything that is heterozygous right this is going to be any type of Al in which we have an uppercase Al uh let's do p and a lowercase Al big p Little P right um that's going to give us some type of intermediate phenotype so an intermediate phenotype is something in the middle that means whenever we have incomplete dominance we're going to have a situation where neither alil is truly dominant it's not a simple um dominant versus recessive relationship but instead we're going to have a intermediate thing in the middle so this is a great example um this example is actually looking at flowers or pink FL four clocks which are flowers a type of flower so you can have some flowers that are red some flowers that are white but whenever you have a heterozygous flower it has the ability to be pink so if you look between red and white together you get pink that is because because this is heterozygous so it's intermediate it doesn't have the dominant red or the recessive white there it's going to be a mix of both okay so that's an example it's called incomplete dominance this is an example again looking at those flowers showing that you have the ability to be red to be white and also a pink which will be a combination of the heterozygous color um when we talked about the plants how we had a P1 generation F1 and F2 in the previous lecture this will be the purely red and the purely white and if you remember that first generation of Offspring is going to all be heterozygous that is where we're going to see that pink color pop up and then eventually at the F2 you're going to see a range of all the possibilities because you have homozygous dominant you have heterozygous and you have homozygous recessive so this is a question I want to have you work on and and let you look through this one so I'll give you a second okay so if you want to continue working on it please pause it I'm going to start the process of um evaluating this particular question okay so in these different birds these um anadan fowls black birds are going to be homozygous dominant and white birds are going to be homozygous recessive a homozygous black bird is crossed with a homozygous white bird The Offspring are all bluish gray show the cross as well as the genotypes and phenotypes of the parents in Offspring so the black bird is going to be homozygous dominant the white bird is going to be homozygous recessive we do our typical punet Square black bird on the top white bird on the bottom we end up getting all heterozygous Offspring so there is a 100% chance we are going to have offspring that are heterozygous and this this means that from the story The Offspring are all bluish gray that phenotype is 100% of offspring that are bluish gray the follow-up question this is really where it gets a little not harder but you have to put your information together is what results if a black individual is crossed with a bluish gray individual so you have to understand that because I didn't tell you what the genotype of the the bluish gray is you need to use your context clues and information from this question to understand bluish gray is this heter biggus feature here so let's say we did another punet Square we have the bluish gray individual on the left and we have the black bird on the top here want to get that cross that cross so what is this mean that means 50% of our birds are going to be homozygous dominant which means they will be black birds and 50% of our birds are going to be heterozygous meaning they're going to be bluish gray birds so that's a good question for you it's another blank slide if you want to work through it all right so that was incomplete now let's look at co-dominance co-dominance is what happens when you have both of the phenotypes are going to be shown here okay so again I'm just we're not going to do a codominance question U but something like let's say a spotted horse or um a ladybug or zebras they're not necessarily codominance but that gives you a good visual of seeing two different types of colors or patterns or something like that present one excellent example of codominance that you will see or have seen is blood typing so this this is showing all of the different blood typing or blood types that we have we have a b which is positive or negative depending on the r factor you have blood type A blood type B and blood type O so these are all going to be blood types and this is a great example of co-dominance why um because based off of the genetics that you receive for your blood type you actually have the ability to showcase the a antigen the B in or when they're together a co-dominant you have a and b so the same way we had spots for a ladybug a black spot and a red background um you see both that's going to be the same thing for our blood type so we will get to some blood typing questions but I want y'all to be familiar with blood typing because it's so relevant okay so if you're the phenotype of a not talking about positive or negative the Rh factor is a little bit different we won't cover that right now but just for your actual blood type if you are blood type A that means you are either homozygous dominant for a or your heterozygous for a so this little I represents nothing so you see this is a letter I with an A on the top that means this Gene carries the a protein this Gene carries the a protein this Gene this lowercase i carries nothing so all you have is basically a and nothing so you're end up being a or you have two A's a a same thing with B you have the gene that carries B the gene that carries B homozygous dominant or your heterozygous B one of the genes carry B the other one carries nothing AB there's only one type of genotype for ab is co-dominant you have one gene that says a one gene that says b so you are ab and then finally um if your blood type O that means you have uh genes that don't carry anything so it's two Al those little lowercase eyes but they don't have an A or B on them so you have nothing um so this is exactly what you see here realistically if somebody's a b you see the spikes you have blue and yellow they're going to have both of them on their red blood cells if they're a they just have yellow B they just have blue and then if you're blood type O you have no antigens on your blood cells so here's a really nice recap of what we've discussed so far um complete dominance that's like let's say the the um red flower or the white flower um that's where you're going to have just a dominant phenotype in complete dominance that's where you have a mixture so here the pink flower represent that mixture and then finally co-dominance is where you have both of them so this flower that is both um a darker color and a lighter color that's going to represent what codominance looks like okay I want to introduce a few more Concepts now that we're in the advanced stage um this concept talk talks about a twoof factor cross so what we've been talking about previously has been a mono hybrid cross I wrote it on the last uh lecture monoh hybrid cross we're talking about one trait now we're going to see what happens when we're talking about two traits or a DI hybrid cross this is how we're talking about inheriting two different genes um at one time this happen because some of the genes that we un cover are linked together meaning that a lot of times when we pass them from one to the next they're kind of are a tag team they're like a partner system so you usually don't see one without the other a great example is freckles and red hair so people that have natural red hair not dyed red hair um but natural red hair tend to have FR freckles because those that red hair and the freckles they are tied together um so even though they are tied together the genes can be independent with how they are passed along um that means that they they're together right so let's say we have freckles and red hair um but it doesn't mean that every time we make a new organism they have to be the uppercase letter they can also be the lowercase letter right same thing here um so that's what the independent part means that we don't have to um only take you know the uppercase or lowercase letter it just means they're independent so as we start switching them around you can get either version because they do have the ability based off of Mel's rule to be able to um randomly be distributed into gamet okay so as we talk about a die hybrid cross I want to show you how we do that it seems very overwhelming but I promise you it is not just make sure that you are listening while I'm explaining it and it'll be a lot easier so this is what a DI hybrid cross will look like um for you and and it's going to follow the same rules that we've talked about the very first time so the very first time we started any Punit Square we said we have to identify the parent so this is y y r r you see we're talking about two genes so in this case the yellow is going to represent I believe the um the color right this represents color and the RR dominant trait is going to represent if it's smooth or if it's wrinkled so it's is smooth so the first step was identifying the parents gamet you're usually going to get that right if not you might say something like you know you're looking at a plant seed that is homozygous dominant for Co for yellow color and um homozygous dominate for smooth seeds and you could then be able to come up with the letters on your own based off of everything we discussed so Step One is identifying the parents genotype step two is making the gamt right if you have an egg and a sperm cell that are coming from this what could go into each egg or sperm cell well we can only pass one gene along at a time so we can do one y and one R so I'm going to give you a little bit of an example that might help us use see this a little bit better let's say this is the yellow um sorry the green one the green Y and the green R our next cell what can we get well let's keep that same green y but this time let's look at the blue r h nice let's do another one so we've done our are green y's we have one here and we have one here so we've already separated them into two cells now let's go and identify our purple y so that's going to go into two cells I'm just going to draw it now purple y purple Y and then after I do my purple y I'm going to go in and grab my green r that was right here the first R we see put that with the purple Y and then I'm going to grab grab the blue R and put that with this one so I know it's like a little bit confusing but I'm hoping that you can at least see with the colors how when we're splitting them up into cells whether it's eggs or sperm cells all we're doing is taking one of each of the genes so these are going to be the the green wise so this one goes here this one goes here and then now we have the green RS goes here uh blue R again again we're just trying to say how many possible combination of these Al can we make we can make four different uh Duos of these Al okay so now again the same exact concept I want you to zoom in or look a little bit here so I want you to um I think I can zoom in if I remember I just can't use my pointer once I zoom in but once you zoom in here look across the top you see the gambits are it says gambits from heterozygous R and heterozygous Y and you're seeing across the top the first one is uppercase R uppercase y I hope you see where that came from then is uppercase R lowercase y then the third one says lowercase R uppercase Y and then the one on the Final End says on the end said lowercase R lowercase y so again from this genotype we came came up with all of the little individual sperm or egg cells you can make from it the same concept is here and then from there all you're doing is just pairing them together putting the RS together putting the Y's together putting the RS together here putting the Y's together here right so this line is going to have all of the Al from this one and then each of these columns are going to contribute their Al so that's how you're doing I'm not going to ever ask you do to draw a full square but I will ask you to create the gamet from this type of parent so again I'm going give y'all some space to practice this is definitely opportunity to practice how you would be able to to do that okay so um we're going to close probably on like One More Concept and then we'll be done so medilan inheritance patterns there are two different types of ways we can inherit genes one is through autosomal genes so autosomes remember are chromosomes 1 through 22 and then the final way to inherit genes are sex linked or xlink genes these are going to be genes that you only find on your X or your y of your uh X or Y of your chromosome so with autoo genes autoo dominant you only need one Al to show a trait so this is what we've been talking about for the most part right let's say you have something like uh ww that's going to be autosomal dominant if it's coming from any of these chromosomes from 1 through 20 2 Auto recessive some diseases are Auto recessive where you need two alals to show the trait and you're going to need uh these Le to be recessive alals something like CLE cell which we'll talk about in just a second is autoo recessive you need both of these little letters to have the CLE cell disorder um and then Sex Link or xlink disease we'll talk about that in a second so let's focus to Cle cell um which is a an example of uh a aoom or recessive Disorder so the question is what are chances two individuals that are heterozygous for auto recessive gene have healthy not carrier children healthy carrier children or affected children so take your time and see if you can answer this question okay I will start it and if you're so working on it please pause it don't let me just writing stop you from working on these okay so the first thing you need to do is say heterozygous what does that mean that means they're going to look like this I'm using the letter c um aama recessive means for me to have the disease I need to have two recessive alals so I said two heterozygous indid individuals for Cle cell I have a c here c c c so now I'm just doing my regular match like I normally do so if you couldn't get there at least pause and see if you can answer these questions based off of my Planet Square okay so what percentage of the children are going to be healthy not carrier children the only one that is a healthy non-carrier child is going to be this one it does not carry the CLE cell Gene at all anymore so so the percentage or the chances will be 25% or 1 and four so every time this couple has a child they have a one in4 chance of having a child that is healthy and does not have the um CLE cell Gene that they carry what is the odds they have a healthier carrier children that number is going to be different so these children will not have the disorder because the disorder is aoom or recessive but they will still carry the trait to pass on potentially pass on to their children or their offspring that's 50% or two of four and then finally percentage that are affected that's this last number here at the bottom so I'm using the same color but that's my color here at the bottom that's 25% so remember it's random assortment so every time this couple that we just drew on the screen um has a child they have a 25% chance of having a child with sickle cell a 50% chance of having children that are healthy heal but carry the CLE cell Gene and then a 25% chance of having children that are healthy that don't carry it at all so every single time is random because every time they produce sperm or eggs it's just a random mix okay so some of these exellent tricks this is important because um some of the genes that we have are only found on some of those X um chromosomes we have so the X chromosome is a lot bigger than the Y chromosome so let me backtrack a second and show you that X here is a lot bigger than y so females are XX while males are XY um so because of that there are some genes that we have on the X chromosome but we don't have them on the Y chromosome that makes them be known as xlink genes okay so some genes we have are only found on X so let me just draw a little example let's say this is X this is y if we're talking about a certain type of Gene and it's only found here on X then look there's nothing there on the Y so whatever you get on the x is going to be what you have because you only have one this puts males at a disadvantage because males of course only have one X gene they are XY while females are going to be XX so whatever mom gives the boy on the X Gene is what the boy is going to have right um that's why a lot of disorders that happen in men are a lot more common um than in females right the example here is um color blindness so color blindness is more prevalent in men than in women that is because the mom let's say she has well not let's say she does have two x genes XX the dad XY let's say this mother is um normal she does not H she does not have the the um color blindness but she does have she's a carrier for it so she carries it in one of her ex's however the other X overpowers it so that's why Mom is not color blind dad in this case he has a normal X chromosome and a y chromosome he doesn't carry the XG whenever they make their eggs in sperm mom is going to give off the regular X and then the X with the carrier the regular X and then the X with the carrier and then Dad will do the same thing he will give off his x's and he will give off his y's and his sperm those are the only chances he has so now you're going to see um something we haven't talked about which is gender you're going to create not only traits so be able to see if The Offspring or color blind carriers or normal but you'll also be able to pair that with their gender because now we can identify if that Offspring is male or if they're female so here's a good question and I'm going to show you how to draw this about xlink or Sex Link genes so what um are The Offspring between a female who is a carrier for color blindness and a male who has color blind okay so the thing about this question is before I even give you time to work on it on your own I want to help you identify how to draw this because we're kind of working with two letters here we're working with chromosomes either X or Y and then we're also working with color blindness right color blindness there or there um we have to first come up with a a different way to draw it so the same way we kind of Drew our blood typing you can draw it with either X and then this being a b or a B that one or Y paired with either the b or the B um so make sure when you draw this that you pay attention to how you're putting that in the box right so when you're making your male so let's put the dad on the top he's going to be x y and then the female on the side and then I'll let you put whether it's supposed to be big b or little B but that's how you should draw it so that when you have your punet Square you will eventually have some x's here and then you will also have some x's and a y here paired with that b so now from this point you should be able to look at this question and then fill in basically the little SPAC that would go in this area Okay so if you working on it I'm about to start working on it on my end so just wanted to give you heads up all right so we're talking about a female who is a carrier and a male who actually is colorblind so for the female she's a carrier meaning she's going to be heterozygous so for our female make my ex a little clear we're going to make her Big B little B I'm going to get rid of my lines it be a little clearer to [Music] see the Dad we said he's a carrier remember it's only on the X so we don't need to put anything on the Y right get rid of that get rid of that and I apologize I drew it the first time I was on robot mode so we have identified dad as being color blind so now we want to give Dad the color blind Jee it's going to be a lowercase b because we already showed mom as a carrier that has that uppercase B so now we're just putting together everything of course I already pre-wed x's in there but if you were drawing this for the first time you would have to draw the X's um and then this one we just have an uppercase B dominant and then a recessive B so this is what you have the question here is asking specifically about males and females sometime you might get a question that say like out of all of their children all Offspring and that's where you can just look at the whole whole big picture but I want you to focus that I'm asking you certain questions of males and females so if I just said out of all their children how many will be color blind you would look at this and say well you're going to have this one is going to be color blind and this one is going to be color blind out of all of their children they have a um 50% chance of having children that are color blind now if I ask you how many affected males out of their males what percentage of their males are going to have color blindness right what percentage of their males um if I ask how many males are affected the number would be one male is affected but if I said what is the percentage of your males that are affected the N it would actually be 50% of males are affected because you only have two males and if one out of your two males are affected that gives you a 50% affection affected rate for your males because that's only right here for our females um how many females you have that are going to be color blond you have one female that is going to be color blind that's going to be the female at the bottom and if I said what is your percentage of your females that would be color blind 50% again will be color blind because one out of the two females you have is going to be color blind so I just wanted to give youall an example of how the XL version works um and then finally I just wanted to show you what a pedigree looks like a pedigree is just a um way to draw how traits are passed from one generation to the next so it incorporates things like gender um if individuals are affected they will be all they will be um filled in with black if they are unaffected they will be a open circle and then if they are potentially potentially a carrier will have half of a circle so I'm just showing you kind of a family tree essentially generation one generation 2 Generation 3 that shows how genes can be passed along I won't have you identify this I just want to show it in case it pops up anywhere so this concludes the lecture but again as you see this is extremely active so my suggestion would be to Google any type of Punit Square problems you can get look at the documents that I've put up on the module 4 folder under uh I think module 4 practice or or module for exam prep or something like that make sure you do as much practice as you Poss possibly can so that you can be prepared for um any types of questions you see all right so this concludes our lecture please watch it if you have question saving for class