X-Linked Recessive Pedigrees

by Jason Amores Sumpter
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in this video, we're going to talk about the X linked recessive pedigrees and so excellent process of pedigrees are, of course, going to be pedigrees that depict an excellent recessive disorder and typically these excellent process of pedigrees. They show that mawr males are going to be affected than females. Also, females of an excellent recess of pedigree can Onley be affected if the father is affected and the mother is either affected or at least a carrier, or is at least hetero zegas for the disorder and all sons oven affected female will be affected when it comes to X linked process of disorders. And so if we take a look at our example down below, we can see a pedigree of an excellent recessive disorder. And so here we can label this as an excellent recess. It disorder, and really, it's looking at red green color blindness, and so red green colorblindness is an X linked recessive disorder. And so having an ex capital B means that it's going to be the normal vision that, uh, where the individual would not be color blind with this Khalil. But it's the X lower case B that is going to lead to having this particular color blindness. And so again, because it is an excellent recessive disorder, females are going to need to have two X lower case bees in order to be affected, whereas males Onley need one X lower case B to be affected. And again the affected individuals are the ones that are shaded here. So they're the ones that have the filled in black boxes, and which will notice is that all of the ones that have a filled in black box have X chromosomes. Onley have X chromosomes with, uh, the recess of Alil, and so notice that there is a large tendency for males to be effective. And so the vast majority of the people affected in this case are males. There's only one female that is effected here in this scenario, and that is a pattern that will help you identify X linked recessive disorders much more quickly. Just by looking at thio to see if mawr males are significantly affected than females. Now, notice again that a female can on Lee be affected if the father is affected and if the mother is at least a carrier. And so when we take a look at this female that is affected. She could only be affected if the father is affected and notice that the father is affected. And again the mother is a carrier, meaning that she is hetero zegas. And so that's the Onley way that a female can be affected. And of course, all of the sons of an affected female are going to be affected. And so notice that the Onley son of this couple is affected because the mother is affected. And so this year concludes our introduction to X linked recessive pedigrees. And once again, the biggest thing that you should be able to take from this is that Mawr males are going to be affected than females. And that is a big clue to help you identify excellent recessive pedigrees. So this here concludes this lesson and I'll see you all in our next video.