chapter 13 chromosomal inheritance your quiz this week kind of covers some information from both chapter 12 and chapter 13 um I cut a little bit of chapter 12 I cut a fair amount out of chapter 13 or try to simplify it so hopefully this will not be as long as the other slideshow but they tie together really well and they're they're done together and the lab covers stuff from both of them so I needed them both in one week it is a lot of information and kind of need to know this before we go to what we're covering next week which is DNA replication um it's going to all tie together this unit is a little bit hard to do in order as um sometimes it's better to do the next chapter we're doing before we do this cuz they're like really intertwined and you kind of have to understand both to understand either so there's not necessarily a good order to do it um I find it a little easier to Do genetics and chromosomal inheritance first and then DNA replic but um next week is also a lot uh and fairly complicated so do try to understand all of this before we move on to next week stuff and know that your quiz will cover information on both the last slideshow and this slideshow so this was uh from chapter 12 a triy hybrid cross essentially if you're doing three traits you could make a big punet square like you did for one one trait and two traits but it would be 64 squares large and that becomes very inhibitive so there's a much easier way which I'm going to show you on the next slide of how to do um a three trait cross so try hybrid is when you have the true breeding true breeding the F1 and then the F2 so when we talk about the hybrids is when you start with your P generation is true breeding but it doesn't matter your parents for two trait or three trait Cross or even for trait your parents what the genotypes are for as long as you have the genotype of the parents and you're and it's asking like what's the probability or chance of having an offspring with like this combination of traits um you can figure that out really easily that's also what makes you unique is because you are these different combination of traits so you could figure out with even just like five traits the chances of getting from two paent these like specific five traits together it's actually very low so I'm going to show you um a probability method the next slide I think talks about probability with multiplication again it was from that was from your chapter 12 notes that the book provided to try to explain probability uh if you understand that it makes it easier but I'm going to show you how to do it so as long as you know what to do it's it's fine I don't have a lot of room to write here but try to do this um so say you're giving a uh example you're giving a two parents genotypes one parent has this genotype and one parent has this genotype for four different traits trait a trait B trait C and trait D doesn't matter the traits they could be any trait they're just different traits and they have um two alals for those traits men equal probability of getting either Le for either for each trait the traits aren't linked that would have to be specified too and it says the question is like what's the probability of having an offspring that is recessive for all four traits so the way to break it down is look at one trait at a time and then you times the probability of each of those traits together to get the total probability of having all of those um so we look at our first trait a trait one parent is heterozygous the other parent is heterozygous so let's look at the probability of being recessive for that trait you can just make your punet Square you just need to make one punet square for each trait and by the way you can do this for two trait crosses for three trait crosses or four trait crosses five traits on and on so here's my rough little punet square both parents are heterozygous I'm separating the alal on either side okay and then i' fill it in I'm only concerned about the little a little a so right all the other ones are going to have at least one big a so my little a little a is what 1/ 14 so you could do this as decimals or fractions on the test you won't have a calculator so I say do it as a fraction because you could do these in your head so it's 1/4 now let's look at trait uh the B trait being BB maybe I should Circle it Circle it so we have a heterozygous one parent is heterozygous the other parent is recessive so we need to separate out B from one parent and B this is one parent and then the other parent is Little B little B okay so now we only care about the little B CU we're only being recessive so we can just do this over here little B little B little B little B and then one parent is what is that uh two fours which is 1/2 I find it easier to reduce right away so we'll do 1/2 and then C let's look at I'll make a triangle here C well if we look at c one parent is heterozygous for C the other parent is heterozygous for C we already saw that combination that's what was our a trait work the same so that means our probability is going to be the same it would just be little C little C so it's going to be a 1/4 probability we don't even have to do it again we don't really have that many options right there are only so many options in a punet square so if it's already you've already done a punet square that's going to so show the same thing you don't have to do it again and then let's look at little D being for the D trait being Little D Little D well one parent is recessive the other parent is heterozygous we've already done that with our B so it's going to be the same probability as B cuz we would get the same thing two little D's out of four four so it is 1/2 now we times those all together a lot of times students can do this part conf figure out this but they get confused on our total probably get the total we have to times them all and um sometimes students realize don't realize that when you times fractions you just times the top and just times the bottom uh they try to do they try to add things they try to put them together do something with the top and bottom all your go going is timesing everything across the top and everything across the bottom and that's your new fraction which you may have to reduce sometimes you won't always have one you could have three fours might be a probability um so you can have greater than one on the top and and do always reduce your final fraction down okay so I have ones across the top so one is I put this here one is going to be it's going to be one and then what's it going to be on the bottom 4 * 2 is 8 8 * 4 is 32 32 * 2 is 64 so it's going to be 164th is my chance of having an offspring from these parents that are recessive for all four traits the next slide is a practice problem slide it's a little complicated because it's saying what could be dominant so you kind of have to do the you know for being dominant you could be homozygous dominant or heterozygous dominant so you've got to combine your probabilities look and see if you can do that um and if you want any help with that you can always ask me in lab or office hours or send me an email if you don't understand how to do it there will be one question on the chest that is three or four TR cross and then I won't ask more than that because I know it is complicated background before I get into the chromosomal inheritance um not going to ask you about this stuff on the test is covered in your book but I don't need you to know the the history of all this so Gregor mle is considered the father of genetics but we called him that later he died in 18 I can't remember what s 1884 I believe um without his work being very well known at all which is sad because it was really interesting and really important and it's also interesting because Darwin uh came out with his book On the Origin of Species and Darwin essentially knew there had to be something like Jean some some heritable factor that had to be passed on but he was unaware of mle's work and it's a shame because their work really compliments each other and supposedly um mle wrote Darwin kind of talking about his work because mle knew that his work fit in with what Darwin was looking for and didn't have but um I guess I don't I don't know if this is true uh I guess mle is kind of long and boring and maybe not to the point uh and so Darwin didn't really read it or notice it or pay attention or understand and so mendo's work generally went unnoticed until after uh Darwin's theory of evolution people were interested in finding these heritable factors if this is how species evolve which we'll get into next unit what are these um factors that have to be passed down and so a lot of science were scientists were looking into it and in the year 1900 four scientists essentially independently rediscovered mle's work um and showed things that mle showed but with they were working with different species uh so then it was kind of race was on to what find what is a gene and mutation and how they come about and that really led a lot of genetics in the 1900s scientists came up with the chromosomal the theory of inheritance and remember um theories have evidence to support them explain a phenomena and can be predictive so this is our understanding of how uh chromosomal inheritance Works uh your book kind of goes into more detail of how they got to it uh I'm not interested it's great to know but I'm not going to ask you about that we've got enough to cover so I'm cutting that part out so basically some chromosomal theory of inheritance chromosomes carry the unit of heredity genes so genes are found on chromosomes right chromosomes are the DNA wrapped up with some proteins and then on that DNA is the genes the the genes the information to make the proteins which cause the traits that we could observe in meosis homologous chromosomes separate each chromosome is independent of the other chromosomes so you um write they sets The Law of Independent Assortment each chromosome homologous chromosome separate so you're only getting one chromosome from Mom or Dad in a gamate which leads to next one each parent makes gametes that contain only one set of chromosome suggesting equal genetic contribution from each parent uh and in general that's true we do have a few exceptions and genes can play out differently depending on if you got it from Mom and Dad which is interesting but that gets into more again genetics more complicated stuff than this class covers so right a gamet has one full set of chromosomes but just one set so for humans that's shown down here um the egg has 23 chromosomes the sperm has 23 chromosomes one chromosome one one chromosome 2 one chromosome 3 down to one chromosome 22 or smallest autosomal chromosome and then one sex chromosome making 23 chromosomes and in fertilization shown right this last part the GIC chromosomes combin during fertilization to produce Offspring with the same number of chromosomes as their parent fertilization makes a zygote that single diploid cell uh that has the full both sets for us that would be 46 chromosomes different species have different number of chromosomes so you know the gamt might contain two chromosomes the gamet might contain four the gamine might contain uh 26 chromosomes there's different numbers and so that zygo can be different number but it is right two sets 2 N Diplo chromosomal theory of inheritance and this um this is basing on sexual reproduction slide is a picture of a human female chromosomal female kot type this is a chromosomal male kype so remember the autosome autosomal chromosomes are 1 through 22 and so anything carried on there we would say is autosomal so if you have a genetic disorder that runs in the family that is on chromosomes 1 through 22 we call it AO Al dominant if it's a dominant disorder autosomal recessive it's a recessive disorder or an autosomal dominant trait or an autosomal recessive trait and then you have your sex chromosomes uh we'll get into this a little bit here but X and Y are for mammals and a number of other species when the Y determines the sex essentially when the males are heterozygous meaning they have the two or well actually a different term than heterozygous but it's kind of similar in that uh where they have the two different chromosomes then it's saying the male determines the sex because if you get a y chromosome that is what determines male sexual development two x's as shown on the last slide um causes female sexual development so chromosomal females are XX and they can only give an X chromosome chromosomal males are XY and they can give an X or a y so if a gam of theirs that has a y chromosome fertilizes the egg it will most likely there are differences develop into a chromosomal male and produce male sexual characteristics if the X uh fertilizes the egg it will most likely um cause the individual to be a chromosomal female with xx and um cause generally female sexual characteristics to develop um I'm going to talk about chromosomal disorders coming up and we do have what we call sexlink disorders so when there is a disorder on one of these sex chromosomes I don't know what happened to that red line there we call it a Sex Link disorder because it's found on the X or the Y chromosome the Y chromosome is very small with very few genes so xlink and sexlink are often used interchangeably because xlink genetic disorders the x is a fairly large chromosome with a um number of genes on it that show up in both male and female and are like genes unrelated to sex so we have uh what we call Sex Link disorders are really often like xlink disorders there can be some genes on the Y chromosome that would um only show up if you had the Y chromosome but the Y chromosome is very small and the genes that are active on there are mostly associated with male sexual characteristics so for that reason Sex Link and xlink are used fairly interchangeably the last slide was talking about Thomas Hunt Morgan working with chopa these fruit flies figured out that there was a sex chromosome and there are traits carried on that sex chromosome um and soopa tend to be XY not everything is XY but they were so it it uh was a good model for humans as well because we have this XY system so what happens is when there's a genetic disorder carried on the X chromosome it tends to affect males and not as much females cuz males only have one X chromosome so if they get the chromosome uh shown down here with the disorder on it they show the disorder that is that's on that X chromosome a female shown here has two X chromosomes so if um she gets a disorder that um has an affected ex chromosome generally speaking uh she's considered a carrier because she can pass on that ex chromosome this would like a carrier mother and she could be a carrier but she usually doesn't show the disorder because she has another normal X chromosome and um I'll talk about it in a minute but the the cell will typically kind of turn off the affected one and use the normal one and then the female doesn't display it but can pass it on uh I'll show this in some examples on the next few slides as well so color blindness is an EXL or what we say Sex Link trait because it is carried on the X chromosome um it's not lethal right not lethal be color blind um but let's look how it tends to be um males tend to have it more often than females although females can have it and hopefully you'll see and we'll cover this in lab uh but males have it more often and females are carriers so let's say we have a male who is color blind who um mates with a female chromosomal say chromosomal male chromosomal female who is not color blind um and and this female is not a carrier noncarrier female so she does not have the Leo for color blindness which we are representing by the lower case C in Sex Link disorders sex chromosomes matter so you have to include them in your component Square you have to include your sex chromosome and then the AL what we're talking about on that chromosome for the autosomal disorders we don't care about the chromosome number or anything so we don't uh include it but with sex it matters whether they're chromosomally male or chromosomally female if they're going to have it or be a carrier so we keep it with them so this is going to be represented by the little C and then the Y chromosome which doesn't have the Alo at all because right they're not true um they're not true homologous chromosomes so they uh it doesn't have that Alo so then this female is going to be a carrier and this female chromosomal female is going to be a carrier it kind of looks little but that's supposed to be a big c I'll try to make this one smaller and then both the males will have normal vision no um no color blindness at all but if you think of it so this PE these people would have two if they their chances if they had a son Sons would have normal vision daughters would both be carriers and if you could imagine this imagine a carrier daughter a carrier female I should say who mates with a male who is color blind they could have male and female children who are colorblind so females can be color blind it's just not as common included it as a practice question so I'll start it from for you and then you can finish it out and see if you understand how it works so you have a female chromosomal female who's a carrier and you have a chromosomal male who has color blindness so fill this out in this case here you should have a carrier female in the first box in the second box you would have a female who would have color blindness here you would have a male ale the bottom left one you would have a male who is not color blind and here you would have a male who is color blind so you essentially have all four options and you have a 25% chance of having each in for those children maybe I should have put this slide before because I kind of said it in that last one with these sex chromosomes um females often typically will inhibit one of their ex chromosomes in their cell and so they only use 1 X chromosome um we call this X inactivation and you can actually see the inactivated X that's what we call Bar body but don't worry about that so this is shown really well in cat color in cat fur color the fur color is on the X chromosome they XY system uh because they're male and the fur color is on the X chromosome and so males cuz they only have one X chromosome cat color for these this type of cat can be black or orange right there are different colors but we're talking about this black or orange um and so males can be black or orange because they only have one X chromosome right so the color for they can only be black with their y I'm writing it down here or orange but because females have can be XX they can be have black and orange black right they could be have B for both Al or they could have orange and be black or orange but they could also have the black and orange what happens is One X chromosome is turned off in each cell so as long as they don't have a disorder where they're turning one off the disorder they'll randomly turn off one and produce the other so some of their coloration some of their fur has an orange color and some of their fur will be the black color depending on which X is turned off so you get cats that have black and orange fur color but you don't get that in the males except there are some exceptions which we'll get to later sometimes males can inherit an extra X or something um so with disorders typically the ex the if a disorders on X chromosome that's the one that can be inhibited but that doesn't always happen and so some females will display a disorder even though they're a carrier and they're called manifest carriers where they manifest the disorder because that X chromosome isn't turned off and they show symptoms of the disorder this was kind of all leading up into pedigrees so um pedigrees are way to analyze traits throughout a family history and what they're typically used for is to look for genetic disorder is there genetic disorder and then like as a couple looking at their their each family's history what's the chance of them having a kid that might um have the disorder that's carried in their families so we use pedigrees and try to determine by looking at the inheritance pattern is a trait sex linked or autosomal if it's autosomal is it dominant or recessive is it a single gene or several Gene we're just looking for these we're just going to be using mandilion genetics because when it's SE several genes it's hard to tell and you can't always say even if the autosomal you can have dominant autosomal dominant and autosomal recessive disorders both um you could it would look like it's either one you can't always determine an inheritance pattern by a pedigree but we're going to look at a pedigree and try to to see how they work so with pedigrees squares represent males circles represent females shaded in so here it's shaded represents the person has that version of the trait the nonshaded means the person doesn't so for this pedigree it's a pedigree of a family history with Polydactyly Polydactyly is having six fingers and we already know it's a dominant trait we know it's dominant so this mother here at the top this uh grandmother in this family tree had polya the male didn't they had a son so you typically the oldest one is shown on the left and then we get longer and this by generation so this would be like the first generation often Generations are shown in Roman Noles Second Generation and then like third generation down here in the first generation or sorry the second generation the son had polya and he M horizontal shows a mating mated with a female who did not have poly and they had a daughter who uh did not have polya this couple again going back to the um grandparent generation couple generation one here had a daughter without polya and then they had another their youngest son had polya he made it with a female without polya but he had three kids a daughter and then two sons with polya so that's kind of the way it works um the next slide describes how they worked and then I've got some examples okay the last slide said kind of like what you have affected male unaffected male affected female unaffected f F so shaded means representing this trait that we're trying to look at and you have to determine whether that's the recessive version or the dominant version or is it excellent things to look for and remember when you're doing these um if both parents don't exhibit a trait so if I look down here in this okay a parent has the trait and one kid does a parent has the trait and one kid does okay I can't really tell if that's dominant or recessive because that could happen with both but but if I keep going I have two parents here who don't have a trait and then their kids do that tells me it's recessive and if I look it's a female who has it if a female has an xlink disorder her dad would have to have the disorder because she would have to get an X from each parent so I know it's not XL and I know it's not dominant because dominant if one of these parents was dominant why am I um one of those parents was do they would show the trait the fact that they don't show it but a kid does tells me it's recessive so I know that this is an autosomal recessive trait on the other hand something to look for I have two parents who have a trait and then they have kids who have it and don't have it well if this was recessive just imagine they've got two right we can figure out genotypes from these as well which we're going to be doing in lab and I have practice problems for you if they were both re recessive every kid would have to be recessive so they would have to show the trait they're they have a kid who doesn't so that tells me that they're not it's not a recessive trait it's a dominant trait it also tells me what their genotypes are since they had one kid who didn't have it they each had they each had to have a big big a to show that trait and they each had to have a little a to have the kid who didn't have the trait so this kid is recessive and then these two are dominant uh and their heteros oh no they could be these either kid I don't know the other Al they could be could be a dominant a cuz they could have got one from each the capital A got one from each parent or they could have been little a either way they would have done it but this person I know is little a little a because they don't show the trait so and then if you only have men showing up with it and their parents don't have it it's likely EXL but there you can't always tell I'll try to explain that hopefully if I have an example pedigree pedigree of um this genetic disorder that causes urine to turn black in the presence of air it does have some Associated Health consequences with it and with pedigrees once you figure out the inheritance pattern you can go back in and put genotype in so in this pedigree see two parents even if I didn't know their genotypes so let's look down here yellow is unaffected blue is affected so I have a parents here who are unaffected but they have a kid who is affected so I already know it's recessive so that tells me every blue person has to be little a little a and every yellow person has to have at least one big a because they don't have it I don't necessarily know their other Leo but I can figure it out for this couple at the first generation I know since their kid has it little a little a one parent had it but they can only get one Al from each parent so this Al had to come from the other parent which tells me that this parent had to be a carrier this person this male married a female carrier but they had three kids one who had it one uh we actually do know this person's genotype this person's genotype because it was their kid has to be big a little a because they had to get get the little a from a parent so this person's a carrier and this person's a carrier they're unaffected so they have the big a but they have to have a little a they M it with I said married I should say m it with they don't have to marri a mate M it with a carrier they have a kid who has it now this daughter second daughter here we don't know they could have inherited they have a big a because they're unaffected but they could have inherited a big a from each parent or a little a so this one is a question mark we don't know we do know this one it shouldn't a question mark I feel like the book messed up there you do know what that is because that parent can only give a little a and this person we also know this parent genotype they don't have it so they have to be big a and then they had to pass on a little a for their kid to have it so they have it he what inheritance pattern is going on here I hope you notice something that you have parents who don't have it and kids who do daughter has it if daughter has it her father has to have it he does not so this tells us it's autosomal dominant this also if you follow the pedigree or to cousins marrying this is a reason why it's not great to have uh inbreeding because recessive disorders show up you also tend to get uh immuno issues people tend to be lower immunity when you're they're inbr um and so not a great idea to marry cousins which is going to be shown on the next slide with the Royal British royal family oh also if you can think of what what genotypes you can figure out for this I will have practice ones you can do and you can always have me check them but um definitely when you do a pedigree see if you can figure out the genotype that will help you determine if you've picked the right inheritance pattern or not does this make sense so here's a British royal family um and this is the inheritance pattern of people who had hemophilia so if you notice who all is having hemophilia see it's the Shaded squares that indicates it's an exlink disorder if this was just a small pedigree I would tell you don't necessarily assume it's XL because it could also be recessive right like if we just looked at this first generation and second generation that could easily be autosomal recessive or EXL I wouldn't I I would say you could not determine what it is it's one of those it's not dominant because the parents would have had a haveit if it's dominant but the fact that we see this throughout a larger pedigree and it's always males in four generations here and many offspring indicates that that is um EXL because uh somebody else would have shown up with it uh and it follows the EXL inheritance uh and also another reason why it's not great to marry your cousins even um even if it's like like second or third cousins if you keep doing that in multiple Generations uh you start to become too inbred and disorders can show up pretty prevalent pedigrees and then consequences of non-disjunction were the big things I wanted to go over for chapter 13 so we did non-disjunction said what it was back in meosis of unit 2 remember that is when the either homologous chromosomes don't separate or the sister chromatids don't separate during meosis and you get a resulting you get gametes that either have an extra chromosome these plus one have the extra chromosome or are short a chromosome um if it's meosis one every chromosome has the wrong I mean every gamet has the wrong number of chromosomes if it happens in meosis 2 you only have two chromosomes with the wrong number one long and one short what does this mean what are the consequences well the consequence of a gamate that is short a chromosome or long extra chromosome becoming the one that is fertilized means that that zygote is missing one of its chromosomes or has an extra chromosome that can have very severe consequences and also could be maybe more mild depending on the chromosome let's look at the next slide and slides nondisjunction in meosis if a gamt is made it's called annual Ploy meaning it either has an extra chromosome or missing a chromosome annual Ploy is a gain or loss of a chromosome having um being short a chromosome is called monosomy so if there's only one version of that chromosome it's monosomy having an extra chromosome is called triom in most cases of having an extra chromosome or being short of chromosome that fertilized egg does not survive it may start developing so that zygote may go undergo mitosis a lot of genes are turned off early on just to go through mitosis and grow and so you don't have as many turned on when that thing becomes this ballis cell that's now going to start developing specialized tissue and has to very specifically turn on and off genes on different chromosomes if there's an extra chromosome or shorter chromosome the cell doesn't know how to deal with that and often it will start developing this is a chromosomal error this is not a genetic disorder genetic disorders is the gene on the chromosome is affected this is the whole chromosome or is missing or has an extra one missing a chromosome being monosomy is almost always lethal except in sex chromosome for autosomal chromosome so your 1 through 22 chromosome missing a chromosome will almost always result in what we call spontaneous abortion that's the medical term the colloquial term is a miscarriage essentially that fertilized egg if it starts developing which it may at some point will stop developing and then the uterus that's why it's called spontaneous abortions hormones trigger it to push it out because it stops developing tromis are a little different so the larger the chromosome the more genes there are on that chromosome so having a triom of our larger chromosomes is typically lethal and will end in a spontaneous abortion and not develop the smaller ones there are chances of surviving so some of the more common tricomes are 13 15 18 21 and 22 13 15 and 18 typically will not uh fully develop and often end in a spontaneous abortion or miscarriage but it it can be at different times of development some will get further than others and some sometimes children are even born they might um often uh a pregnant person may go into labor early if they have this type of triom but the offspring that is born typically dies within the day or few days the M Maybe Will Survive a a few months that's even rare but it would be on the smaller like the triom 18 seeing as that's a smaller chromosome you can see down here um May survive a few months but does not live to develop on the other hand having a triom oh excuse me 21 and 22 those happen occasionally um they you can survive with those you can have an extra chromosome 21 or 22 they do have Associated Health disorders and they have a physical appearance that you can tell so triom 21 is what we call down syndrome you are probably familiar um with people with Down Syndrome that's having usually a full extra third 21st chromosome but sometimes there are some cases where it's um it's just like an elongated 21st chromosome we'll get to what that looks like in a little bit but really it's just like one one of the 21st chromosomes is actually longer than the other one um but most are from having three 21 chromosomes and that is due to a non-disjunction age can influence the risk of this which I'll show talk about in the next slide of any tromis particularly triom 21 really increases with ag but all the tricomes actually increase with age and then the sex chromosomes are a little bit different I have some slides on the sex chromosome which is beyond what the book is uh but I do think it's good to know especially in today's world where people are always like arguing about this stuff and don't realize that there's actually a lot of different options and things that can happen um to produce people that are not always clearly male or female and so there can be tromis and monosomies on the uh sex chromosomes that we can survive with um but there are phenotypic differences uh which I'll talk about on the coming slides so I don't know if you remember but back in meosis at the end of the meosis slide I talk about uh sperm spermatogenesis and ogenesis and we did it in lab how human male and female make their gamt and remember females start out with all the eggs she's going to have um or they're going to have as a fetus and then start finish meosis once a month once they start going through puberty and finish that meosis one and meosis 2 only if it's fertilized um later in age so the consequence of that is that as a chromosomal female ages and ovulates the older well whether she ovulates or not because birth control does not affect the um this non-disjunction it doesn't make it more or less likely it's really just the same with age as a chromosomal female ages particularly 35 up the chance of non-destruction drastically increase so there's really this very slow increase shown here from puberty 235 um that increases chances of non-disjunction on the 21st chromosome I believe 22nd chromosome as well it's like all non all chromosomes but because they're small and not as many genes on the 21st uh chromosome it seems to happen it's occurs more often than some of the other or most the other chromosomes um and then after 35 particularly after 40 like if you look between 40 and 45 there is a major increase so but time like a person's 45 they have like a um much greater chance of having uh a child with Offspring um so non-disjunction I think it's like close to a third but time they're 45 um non-disjunction increases with age uh particularly on that 21st chromosome which makes uh over 35 and over 40 a person more likely to have an offspring with non-destruction I mean excuse me from non-destruction with triom 21 what about non-disjunction on sex chromosomes this part on this slide is usually covered I have a little bit more information again because like it's in the news and it's in our society and so I think it's important to like know some of these differences but only with on this slide would be addressed on a test the next slides are related to this are for informational purposes uh related to the non-disjunction sex chromosomes there could be information after that it's on the test I forget what's after the next few slides but seeing as I got six more to go there's probably more on the test after this so don't stop here um so non-disjunction on autosomal chromosones often the fertilized zygote does not fully develop and survive and ends in a uh spontaneous abortion which we think of or we call a miscarriage on the sex chromosomes individual can survive being short or long an extra sex chromosome depending on what that is so you have to have at least one X remember I said the x is large with many genes so you can survive individuals can survive what we call being X notot that is called Turner syndrome or that individual only has one X chromosome but does not have another so that's a monosomy does not have the other version of the X chromosome people with turner syndrome do tend to be infertile they they um so some of these the people are still fertile and able to reproduce Turner syndrome um is rarely able to make um eggs themselves and uh they tend to have other physical differences so they tend to be shorter in size and the sex organs aren't fully developed so it doesn't really fully the individual may not fully like female because they don't have full uh female sex organs and development so um these are right these type of conditions are often what we would consider intersex individuals cuz they don't clearly show as female or male and sometimes they can even be a mix and some more what's discussed on the next slide or also could be interex individuals so everybody needs an X so if something was um only had a y chromosome and didn't have another sex chromosome whether it be another y you couldn't also survive a two y That's not shown here but you have to have at least one X so if it was just a y or two y's that would be a non viable zygote that's a lethal sex annual pyy so that one would not develop and end up in spontaneous abortion a miscarriage but the others can survive so triple X that's having 3x chromosomes that can survive those people are often taller but because we inactivate an X chromosome sometimes two are inactivated for people with tri X and so they may be able to produce eggs um and are often not much fem phenotypically different than um a double X chromosomal female xxy is considered a male because it has the X chrom I sorry the Y chromosome but they have two X chromosomes so um it does affect this these people are often infertile it's called Klein filters and they may not be clear they may appear more phenotypically female um or again kind of something in between they're often um infertile usually cannot produce sperm or egg um but they may have some development of both or either sex organs but not fully they have weak muscle might have enlarged breath so again they might appear that appear phenotypically female but they're not um producing egg or spurn and have full sexual organ development and then you could have XY Y where you have an individual with an XR but they have two y's that's called Jacob syndrome um and those often can be similar to males with XY so they usually do typically look um phenotypically male and produce male sexual characteristics but um they're often taller there are other Associated things that I didn't list here there's actually quite a bit on all of these but I was just trying to keep them summarized um and they may have learning disabilities as well it does affect their development mental and some of their physical development but phenotypically usually appear more similar to a chromosomal male all right so I have a few more cases of some things that can happen related to genetics and chromosome on the next slid with sex the X and Y chromosome aren't truly homolog homologous because they're not the same size they don't have the same genes they don't have the centrom in the same position but to ensure that they do separate for chromosomal Mal separate in meosis they do typically kind of pair up in a way separate the the each X and Y and then those sister chromatids would separate in um meosis 2 typically crossing over is suppressed between the X and Y chromosome so when they pair up to be able to separate as the homologues crossing over does not happen with them the thing is Right whenever 100% sometimes it can and what that means is there is a gene on the chromosome it's a very um y chromosome's pretty small and there's a gene on there that we call the SR Gene and that um codes for some different stuff but a major thing is testosterone which is a major hormone in producing male sexual characteristics both in development and then again in puberty and so what can happen is when the the X and Y chromosomes are paired up in meosis 1 Al crossing over can happen and the SR Gene can be put on an X chromosome and the Y chromosome would get that part of the X chromosome and not have the sry gene what this means is that you can have an XX which would be considered a chromosomal female individual have the sry Gene and develop male sexual characteristics generally speaking because it's just the gene on the X chromosone um you kind of get a variety of things it can the person again these are inner sex people so that could be more look more phenotypically female or could look more phenotypically male um typically There's issues reproductive issues where they are infertile or unable to produce gameat often because their sex organs are not fully developed you can also have an XY individual who would be a chromosomal male but if that sry y Gene is not on that Y chromosome that person will develop more like a phenotypic female and will generally appear more female and then may or may not again there's variation on like kind of if the X chromosome that had that's or the Y chromosome that's missing the SRI Gene um they'll probably look more phenotypically female but the again the SE the the sex organs may not be fully developed so you get quite you can get quite a spectrum is what I'm trying to say you could have these differences being somewhat more one or very reduced like kind of having phenotypical male parts or phenotypical female parts but they're reduced or you can actually have some of both in in most of these this type of case in many of the cases on the previous slide so there's a lot of variation it's not always one or the other chromosomally or genetically like the way your book described chromosomal structure errors so I simplified it with this diagram which I think is way more easier to understand uh and this is all you need to know is kind of the different types deletion duplication inversion and reciprocal translocation or just I just say translocation um chromal structural errors your book kind of goes into detail in more of these and had an image for each but it was like really confusing so I like this one better and I think it will simplify it so on top of nonest fun getting like a full extra chromosome on one the chromosomes are being short a full chromosome um stuff can happen to the chromosomes themselves when the chromosomes are being copied in SASE and when they separate in meosis sometimes the non-disjunction is not complete where a chromosome can actually Break um so you can have different stuff so a deletion is when like a whole section of a chromos Zone isn't copied and is deleted out like on that sister chromosome sister chromatid excuse me so when they separate one of the chromosomes is missing the gene meaning it'll be much shorter than it should be um that the severity of that depends on the chromosome and wear what genes typically it's not a good I mean it's I wouldn't it's never a good thing but typically it's um can be very severe where it could end up causing essentially the zygote to not develop into the whatever individual of whatever species especially if it's on a large chromosome with lots of lots of genes or there are just very important genes for survival on that chromosome if that's deleted it's not going to be able to survive on some chromosomes though that you do have regions where you don't make you don't have genes like you most of your DNA actually is en coding so there's a lot of part of your chromosomes where you don't have genes that you're making proteins for so you can potentially live with some deletions a duplic is where it's copied and it like double copies the same region so those genes BC get copied again and so you will have the genes repeated on that chromosome and now the chromosome is much longer also than it should be um again depends on the gene survival may be difficult with there if it's important genes but could potentially live with this this could also cause like a tri or what's called Down syndrome is sometimes from an aong chromosome 21 um and inversion is where you flip gen so like the genes are copied but put in the wrong spot so you have right this is the order of genes a b c d here they've been SL flipped so now the genes are in the wrong spot of the chromosome that's a problem because DNA is looking for it when it's making the proteins from these it's looking on it on a certain spot so if it's in the wrong spot it has trouble making those proteins so that's usually not a good thing and then a translocation is actually like flipping genes with a nonhomologous chromosome you're putting the wrong genes on a wrong chromosome usually not a good thing so these are different sort of chromosomal errors that can happen the severity some of them the severity occasionally could be minor most the severity is pretty big where the individuals not going to survive or have pretty severe Health consequences this is just uh um your book The Cry to sh Cry of the cat the babies the sound like a cat crying um is from a chromosomal error that happened a recombination uh happening can cause different disorders so thing I wanted to clarify your book kind of talks about it more but I wanted to note here chromosomal disorders rarely run in families there are some certain genetics that can make it more likely but most chromos chromosomal disorders are either due to non-disjunction or an error during um DNA replication during the S phase or potentially something else with meosis when the chromosomes are lined up and separate um like breaking it like not fully getting a full chromosome but those are all kind of random events that happen that don't really run in families genetic disorders on the other hand run in families cuz that is the information on the DNA the AL are passed on through families they can always show up with every genetic disorder out of all the people who have any given genetic disorder some percent of them come from a family with no history of that because it just happened in mutation all of us Happ have mutations in us in our somatic cells that only affects us but if it's happening in our gametes or our germine cells that affects our Offspring so we have mutations which could be beneficial could be neutral or could potentially potentially be detrimental in our gametes and if those gametes are the ones that fertilize The Offspring has that so while they run in families they can also um show up without having a history of IT thing which I I just want to touch on briefly not going to go into detail your book kind of talks about a little bit some species can live with ex more than two sets of chromosomes um for the most part animals do not live well as polyes so this is having a full nether set so like for humans this would be if we were to Tri Ploy a third set of chromosomes we would have our 46 and then we would have another 23 making us uh 69 I guess is no yeah 69 chromosomes right we couldn't live like that it's getting a full another set you could be 3n 4N so on up I've heard of as big as Aiden that's what the strawberries we eat are aen I don't know how big they can go PL can survive like this very few animals can although some can I think I've mentioned before earthworms are three in most animals do not survive polyploidy um many plants can and a lot of our crops are polyploidy they tend to make being poly tends to make them larger produce more of something and plantss can survive like that so a lot of our crops we have made polyol because it makes them larger or juicier maybe more sweet or something like that um so poly is just having extra sets of chromosomes or crops are a good example of this um plants can survive like that animals can't that's everything I've got about genetics and chromosomal inheritance I know it's a lot um lab will be very helpful next week so uh hopefully you kind of know the stuff and then we'll do be doing lab next week uh touching on it which will help put all of this into practice