In this video we're going to introduce pedigrees. And so a pedigree is a chart or family tree that depicts family relationships, and pedigrees can be used to track a phenotype over many generations. Now within a pedigree circles are going to represent females, whereas squares are going to represent males. Now shaded or colored shapes are going to represent affected individuals that do have the phenotype of interest. And then horizontal lines that go from side to side are going to connect to mating parents, whereas vertical lines that go up and down are going to be used to connect parents to offspring. And so if we take a look at our example down below, we can get a better feel for these symbols and connections on a pedigree. And so notice that circles that are not shaded represent unaffected females, whereas squares that are unshaded represent unaffected males. Now the shaded in circles and squares represent affected females and affected males respectively. And when we say affected, we mean that they actually have whatever phenotype it is that is of interest. Now when you see horizontal lines connecting two shapes, this represents mating parents. So this would be the mating male and this would be the mating female. Now down below what you'll see is the vertical connections that you see will connect the parents to the offspring which we have down below. And of course if these offspring are connected like what we see here that means that they are going to be siblings coming from the same set of parents. And so as we move forward in our course, we'll be able to talk more and more about pedigrees and how to read them. But for now this is our brief introduction to the symbols on a pedigree and I'll see you all in our next video.
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concept
How to Read Pedigrees
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Video transcript
In this video, we're going to talk a little bit more about how to read pedigrees. And so pedigrees are typically read from the top to the bottom by starting from the 1st generation. Now in our example down below we're going to use this pedigree over here to determine the relationships between the indicated individuals on the pedigree. And over here what we have are the indicated individuals. Here we're going to put the specific relationships. And again over here we have the pedigree itself. Now the first, set of shapes that we see at the very top represents the very first generation or the p generation if you will. And so you can see that we have an unaffected male because it's an unshaded square, mating with an affected female because it's a shaded circle. And then of course the next generation of organisms that we see here would be the f one generation, the first generation of children. And then, of course, the generation below them would represent the f 2 generation or the generation that is going to be the children of the f one generation. And so, what you'll notice here is that person number 1, indicated here with the number 1 here, is going to be person number 5's father. And the reason for that is because there is a vertical connection between person 1 and person 5, and that means that person 5 is the offspring of person 1 and of course person 1 is a male so that means that person 1 is going to be person 5's father. Now moving on to the next one we have person number 7 which is over here, and person number 4, which is over here are and what you'll notice here is that both of them are vertically connected to the same sets of parents, which means that they are siblings to one another and more specifically because they're both females they are sisters. So person 7 and person 4 are sisters. And then last but not least here we have person number 11 which is down here and person 6 which is up here. And it says person number 11 is person 6's daughter. And the reason that we know that again is because there is a vertical connection between the 2, so that means that, they, this will be the parents and these will be the offspring. And of course 11 is a circle which means that she is a female. So that means that she would be person 6's daughter. And so really this here concludes our example problem and we'll be able to get more practice reading pedigrees as we move along through our course. But for now this here concludes this video and I'll see you all in our next one.
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Problem
Problem
Diagrams depicting family relationships and phenotypes for a genetic disorder are: