X-Linked Recessive Disorder: Hemophilia Inheritance

by Jason Amores Sumpter
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in this video, we're going to talk about X linked recessive disorders as we talk about a specific example in hemophilia, inheritance. And so hemophilia is a disorder that's characterized by abnormal blood clotting. And it is an X linked recess ivo disorder found in humans now by X linked recessive disorder. Of course, the excellent part means that the disorder is associated with the X chromosome and a gene on the X chromosome and by recessive. What it means is that it's on Lee going to be expressive. The individual on Lee has the recess. Yvette Ah, Leo or the recess Ivo A. Leal's on the X chromosome, or X chromosomes. Now females must be home a zegas, recessive or have to recess if a leal's in order to be affected by an excellent recessive disorder, however, males, they only require one recess if I've alil in order to be affected, because they only have one X chromosome, and they only need to receive one recess of alil to be affected. And so because males only need one recess of a Leo that makes males much mawr likely that they're going to be affected by X linked recessive disorders. And so that is something that is characteristic of these X linked disorders that they tend to be mawr likely to affect males than females. And so, if we take a look at our image down below, notice that we're showing you a pundit square that is crossing a hetero zegas mother that is unaffected by hemophilia with an unaffected father that is again not going to be affected by hemophilia. And so the hetero Zegas mother is going to have a new X Capital H and an ex lower case H And again, it's the X lower case H that is going to be associated with the disorder. But ah, mother, that has an ex capital age. A female that has an ex capital age is going to be saved from having the disorder. And so the females need to have to explorer Case H is in order to be affected, whereas the males again on Lee need to have one explorer case h to be affected. And so when we complete this pundit square here, what we'll see is that we can bring down the ex, uh, capital H to these areas here so we can put the X here the X here and again, the Capital H And then we could do the same over here with this theme. X lower case H we could bring that down. So we will have the X and the X here on. They're going to have lower case H is. And then, of course, we can bring across the X capital H two here and over here. So we will have X and X here, and they'll both be capital h is. And then over here we're gonna bring across the why to this position into this position over here. And so we'll have the why here and the why over here. And so what you'll notice is that taking a look at the females the top half over here, uh, the females are going to be unaffected. And so you can see the reason the females are unaffected is because they have at least one capital H one X capital H. And when it comes to the males, which are gonna be down below right here, 50% of them are going to be unaffected. But 50% of the males will be affected. Uh or a least that's the likelihood of that. And so what you'll notice is that it's the males once again that are gonna be more likely to be affected by hemophilia, which again is characterized by abnormal blood clotting, the inability to form blood clots. And so this here concludes our introduction to X linked recessive disorders, specifically hemophilia inheritance. And we'll be able to get some practice applying these concepts as we move forward in our course on. So I'll see you all in our next video.