 Polygenic traits. Polygenic. Most of the traits in you are polygenic traits. Poly, many, genetic genes. Many genes contribute to one trait. One example of this is eye color. And I know I always use the blue eye, brown eye, allele example, which I hope I always remember to say is totally not true. But in fact, at this stage in the game, my knowledge is that there are three genes that contribute to eye color, which is how you end up with a varying shade, is why none of our eye color analyses ever work out, because it's not just simple Mendelian genetics, one gene on one chromosome creating this particular phenotype. Three different genes that are interacting to create this phenotype. Now, we're about to get into some situations where it really does start getting pretty messy. Right now, I can look at you in the eye and say, yeah, three genes, code for eye color. But by the end of this, hopefully you realize that that's sometimes and sometimes not so much. All right. So polygenic traits, one trait, multiple genes contributing to that. Another example of a polygenic trait is height. There are multiple genes that are contributing to this phenotype. Often with polygenic traits, you end up with a sort of bell curve of diversity, of possible different phenotypes, as opposed to either you are, say, a tongue roller, or you are not a tongue roller. Either you have blue eyes or you don't have blue eyes. Like, knowing, of course, the blue-eyed example is completely false. So, some phenotypes are yes or no. Pink, white flowers versus purple flowers in our pea plants. That's an example of something that's really straightforward and simple. But if we had this range, kind of a bell curve example, then we would be more likely to think, oh, I bet there's multiple genes that are contributing to this. Okay. The next one is awesome. Let's try it back to talk about pleotropy.