How to Use Punnett Squares

Jason Amores Sumpter
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in this video, we're going to talk about how to use pun It squares, which it turns out that it is a three step process to using pun it squares. Now we're going to be making a pun. It's square for these two p plant individuals from our last lesson video this pea plant over here, which is Homo Zegas, dominant because it has two dominant Jalil's or to uppercase wise. And this pea plant over here, which is Ho Mose, I guess recess it because it has to recess civil eels or to lower case wise. And so we'll be able to create a pun it square for these two organisms. And so, in the very first step of creating a pun it square step number one. Of course you have tow draw the square itself, which is gonna be a square with four squares within it. But then after you draw the square, you are going to simply align the A Leal's of the parent gam. It's on the top and the left side of the square. And this is going to represent the process of my ASUs and recall my oh sis is GAM eat formation and So notice in step number one again. All we're going to do is align the game. It's of the parents on the top in the side. And so notice that parent number one up above here, uh, is Homo Zegas Dominant has to capitalize. So when it undergoes my oh sis, each of the game meats can on Lee have a capital. Why one capital? Why? And for this parent number two over here, which is ho Mose, I guess recessive to lower case wise, uh, each of its game it's can only have one lower case. Why? Which I'll draw with a lower case cursive here to distinguish it easier from the capital. Why? And so that's it for step number one, Align the A Leo's of the parent game. It's on the top and left side of the square representing my oh sis gamey formation and then in step number two of using the pundits where all we need to do is actually just fill in the pun. It's square itself, and this process is going to represent fertilization or the fusion of the gannets. And so when we take a look at the square this first square over here at the top left. This one's going to represent the fusion of this game. Eat with this game me up here in the top. And so what we need to do is bring down those fill in these gaming. So this capital, why here is gonna go in this position and this lower case, Why here will go in this position. And that represents again the fusion of these two. Gambia's right here in this box that represents fertilization. But then what if this game it fuses with this game, eat over here? Well, then we need to fill in this box right here. So that would be bringing down this capital. Why? To this position and bringing across this lower case. Why over to this position over here? And so we would get this combination on then. Of course, this box down here represents the fusion of this game. Me with this game, Me here in the top, and it once again you just bring down the capital. Why here to this position and you bring across the lower case. Why here to this position and then this last box over here represents the fusion of this game me with this game here at the top. And so again, all you need to do is take the capital. Why here and bring it all the way down and bring the lower case. Why here and bring it all the way across. And so now what we do, What you can see is that we've completely filled in each of these four squares within our pundits square. So we've completely filled in our planet square and we've completely finished step number two, which again represents fertilization or the fusion of gametes. And so step number three here is really just to analyze the results Or, in other words, analyze the possible Gina types and FINA types of the offspring. And so when you take a look at step number three over here, analyze the results of the each of these squares. Which will notice is that each of these four squares is showing a hetero zegas Gina type one dominant Eliel and one recess of illegal and so, uh, recall that the dominant Eliel the capital, why is going to dominate over the recess of illegal. So that means that the capital y the yellow olio is going to dominate. And, uh, each of these squares here represents a hetero zegas yellow offspring. And so what we can say is by analyzing the results that there are four possibilities for yellowfin oh types in the offspring. And there are zero possibilities for green fina types in the offspring again. To get a green phenotype, one of these squares would have toe have to lower case wise. But that is not the case here. And so it's important to note is that each of these squares that you see here represents an equally probable Gina type and phenotype that one single offspring can inherit. So these represent the possibilities. And so, uh, later in our course will be able to talk Maura about calculating probabilities when it comes to pun, it squares. But what's really important to note is that each fertilization event producing an offspring is going to be independent of each other. And so one fertilization event will not impact another fertilization event. And so that's exactly what we mean by independent. One fertilization event does not impact another fertilization event, which technically means that for each fertilization for each offspring, this pundit square would need to be reconsidered and re redone essentially and again. We'll get to talk Maura about probabilities as they apply to pundits squares later in our course. But for now, this here concludes our lesson on how to use pun. It squares, and we'll be able to apply these concepts as we move forward in our course, so I'll see you all in our next video.