Controlled breeding and true-breeding lines

12:45>> this is this is how he did it. He would cut the the stamon, which is the male part. >> Um, or am I No, no, the pollen is the male part. So, he would cut the pollen part and then he would use a brush to take the the sperm effectively and put it in the female part of the of the flower. >> So, this was it was a controlled breeding. Yes. Because the also again the the surface the surface area of how you would do so was was very discreet. >> Yeah, exactly. It's super easy to control, right? And the first thing he does is he develops true breeding lines. What that means is he's going to self-pollinate a bunch of pea plants, which pea plants are totally chill with. They don't care about like, oh, lack of

13:25genetic diversity, all that. They're actually, that's one of the reasons why it's a good thing to use pea plants. And you keep self-pollinating until all of the offspring are something called true breeding. Meaning they always produce the same offspring identical to the parent. It's like you're making clones y over and over. So now what you do is you you're starting out with a clean slate. Yes. Right. There's there's no genetic variability in this plant >> and its um gametes and its sperm and the the egg. Right. It's like if you if I were to take the sperm and the egg of this and combine it, I would just get the same thing again. Mhm. >> So it's like uh a feedback cycle and completely clean, right? For example, offspring of purple flower time purple

14:06flower always going to give me purple flower at this point. That's why it's called true breeding. Okay. >> That so the idea is we we have everyone is effectively genetically >> the same. >> Yeah. And there's no nonsense in the in the like from one generation to the next. I'm not getting weird like effects. It's it's not just that this uh line of the generation is the same. It's that subsequent and prior to some number of generations forward and back are consistently coming in as the same. So you're also removing the idea that oh this one was but the next one might not be. >> Yeah. Yeah. Exactly. So now when I do crosses in I take the parent generation the P and I do a cross let's say from a

14:46purple and a white I'm going to get some weird effects. Right. But I know that's not from the purple doing its own thing or the white doing its own thing. I know it's because of the interaction of these two. Does that make sense? That's why you got to start with that true breeding. >> This is a good This is a really important point which is we're we're creating the canvas from which we're going to test in a way that removes any prior muddying of the waters. >> Yes. >> Uh so that we can look downstream and say we had a clean foundation with which we're building from. >> Exactly. Yeah. And now I can isolate the effect to an interaction between two individuals that have different genetics. >> That makes sense. >> Okay, here's what he observed. Okay, so