Test Crosses

by Jason Amores Sumpter
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in this video, we're going to begin our lesson on test crosses. And so what you may have noticed from our previous lesson videos is that FINA types do not always reveal the Gina type. And so, for example, we could have a yellow P. But we don't necessarily know just from looking at that yellow p if that yellow P has a Homo zegas dominant Gina type with two dominant Leal's to capital wise, or if that yellow P has a hetero zegas genotype with Onley, one dominant illegal and one recess of illegal. And so once again, just because we know the phenotype is yellow does not mean we know what the Gina type is. It could either be homos, I guess, dominant or heterocyclic. And so the question is, how do scientists determine what the Gina type is in a scenario like this one? Well, in some cases, scientists can use what are known as test crosses to test or identify the Gina type of an unknown mystery parent with an unknown Gina type. And so the way that test crosses work is that the mystery parents Gina type can be identified by cross fertilizing, cross fertilization with a known homo zegas Recess if Gina type. And so, if we take a look at our image down below notice on the left, we're showing you a mystery parent who you can see. We have a detective here trying to figure out what is the Gina type of this mystery parent. We have a yellow pea plant or yellow piece, but we want to determine what is their genotype. Is it homo zegas dominant, or is it hetero? Zegas? And again, we don't know which one of these two it would be. So this is why this is the mystery parent. And we can take this mystery parent and cross this mystery parent with a known parent. A parent who's Gina type we know is homo Xigris recessive to lower case wise, which would create these Greenpeace here. And so you can see this little light bulb here saying, I know because this parent has the known Gina type. And so when you cross the mystery parent with the known parent who is home a zegas recessive that will reveal the Gina type of the mystery parent and we'll be able to talk about exactly how that will work and exactly how test crosses work in our next video. So I'll see you guys in that video