Self-Fertilization Experiment: True-Breeding vs. Hybrid Plants

by Jason Amores Sumpter
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In this video, we're going to introduce Gregor Mendel's self fertilization experiment, which helped him distinguished between true breeding and hybrid plants. And so true breeding is highly linked to Ho Mose ICUs plants and Gregor Mendel called true breeding plants, plants that would self fertilized and produce offspring with the same phenotype as the original parent. Now hybrids, on the other hand, are highly linked to hetero zegas organisms and Gregor Mendel called hybrid plants. Plants that, upon self fertilization would produce offspring with mixed phan, a types that are not always the same as the original parent. And so mono hybrids eyes just a term that refers to organisms that air hetero zegas for just one specific trait or gene. And that's because the root mono is a route that means one. And so again, mono hybrids are hetero zegas for one specific trait or gene. So if we take a look at our image down below, we can better distinguish between true breeding pea plants and hybrid pea plants. And so notice over here on the left. What we're showing you are true breeding pea plants and so notice that we have over here on the left a homo Zegas dominant plant that has two dominant alleles to capital wise and notice that this homicide is dominant plant is being self fertilized, meaning that it is fertilizing itself. And so in that scenario, we basically have, uh, Hamas, I guess. Dominant being crossed with the same exact Hamas, I guess. Dominant. So we have to capital wise as the game meats across the top and the sides of our planet square. And of course, this creates, uh, organisms, offspring that have the same exact genotype and phenotype as the original parent. And so this is why all of the offspring are going to be yellow. And that means that this is part of true breeding. Now, over here on the right hand side of true breeding, we're showing you a Hamas, I guess Recess it plant that is green. And, uh, notice that this home is I guess recessive plant is being self fertilized. So we're having ah, Hamas, I guess. Recessive cross with another homos, I guess. Recess of which is itself. And of course, that's going to create offspring that are all homo zegas process of all green offspring. And all of the offspring have the same phenotype as the original parent, which means that this is another example of true breeding. However, what Gregor Mendel noticed is that sometimes when he crossed yellow plants that they did not create true breeding results. And so over here, notice that this is showing the hybrid plants and the hybrid plants. Turns out our hetero zegas, meaning that they have one dominant Elio and one recess of a Leo. And even though they have a recess of Alil, you can't tell just by visually looking at them because the recess of Lille is being masked or hidden by the dominant Eliel. And so this plant appears yellow just as the homos. I guess dominant one would appear yellow. However, when you self fertilized this hybrid plant over here, what you get our results that are different than the true breeding results and what you end up getting. Of course, when you fill in this pundit square, you get the homeless, I guess dominant here you get a hetero zegas here, you get another hetero zegas here and of course you get a homos, I guess recess it in this last box. And so what you get is a mixture of offspring with the hybrids. And that's what we're showing you down here is that some of the offspring are going to be green, so you get a mixture of offspring, and that is how these hybrids were identified. And so Mendel's discoveries, using self fertilization intrigued him. He became fascinated by this, So what he began to do is cross fertilization experiments using pea plants where he would again take pollen from one male plant and transfer that pollen thio pollinate or fertilize another, uh, plant the female organ of a different plan. And so this year concludes our introduction to Gregor Mendel self fertilization experiments and how he was able to distinguish between true breeding plants that produce organisms that have the same exact phenotype as the parent from hybrid plants that created a mixture of offspring upon self fertilization. So we'll be able to get some practice with this as we move forward in our course, and then we'll talk about cross fertilization experiments. So I'll see you guys there