Genes & Alleles

by Jason Amores Sumpter
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In this video, we're going to briefly introduce jeans and a Leal's and so jeans air defined as small segments of D N A. That are going to encode very specific proteins. And these proteins can go on to lead to the expression of a specific trait. And so, for example, there could be a gene for eye color. And of course, because this is a gene, it means that it's a small segment of DNA, and it's going to code for a very specific protein in this protein, in this case is going to lead to the expression of a very specific trait or a very specific eye color. Now, of course, we know that people can have different eye colors. Some people have blue eyes, some people have brown eyes. And so, of course, this means that there could be different versions of genes, so there can be a gene for eye color. But there could be different versions of the gene for eye color, and this is what scientists refer to as Ah Leal's and so Leo's air defined as alternative or different versions of specific genes. And so once again, there can be a gene for eye color, but there could be different versions of the gene for eye color. There could be a version of the gene for eye color. That's a gene for blue eyes, and there could be another version of the gene for eye color. That's the gene for brown eyes. And so the blue eye and brown eyes represent alternative or different versions of the gene for eye color. And so the blue eye and brown I represent different Khalil's. Now it's important to note moving forward in our course that Ah Leal's are typically represented using capital and or lower case letters now moving forward in our course in a different video, we'll talk Maura about genetics and how these different folios can interact with each other in a deployed organism. But for now, just for the sake of unexamined I'll, we're saying here that perhaps the Capital Letter B could represent an alil, or specific version of a gene for blue eyes, And the lower case, Letter B could represent another alil, another version of the same gene for brown eyes. Now, if we take a look at our image down below it, the wheels for eye color, which will notice is that we're showing you these two replicated chromosomes. We have one replicated chromosome over here on the left and another replicated chromosome over here on the right hand side. And so what you'll notice is that these air replicated chromosomes because they each have, uh, to sister chromatic IDs. And so those are the two Sister Crowe motives for the left one and the two Sister Chrome is over here. Sister chromatic IDs are highlighted as you see, so we know that these are replicated chromosomes. And what's important to note is that here there are, uh, a version of a specific gene and alil represented with a capital letter. And so this would be for, for example, just gene A. And this is the capital letter version of Gene A. And notice that this chromosome over here also has the capital letter version of Gina. So these represent identical genes. Identical a Leal's. But notice for this other gene on the chromosome for be that this one over here on the left has the capital B version of this gene or the capital B alil, and this one has the lower case B version of the gene or the lower case be illegal. And so, again, just for the sake of our example, perhaps the Capital B version of the gene would represent the blue eye. Oh, Leo. And so notice that the capital be here is coding for the blue eyes, and so you can see an individual here with blue eyes. And then perhaps the lower case B represents the alil for brown eyes. So this is the brown eye khalil, and so you can see an individual here with brown eyes. And so it's these jeans and a leal's that air, really going to, uh, be responsible for a lot of the traits that organisms display. And so again, later, in our course, we'll get to talk a lot more about genetics and the combination of these a Leal's within a deployed organism. But for now, this year concludes our brief introduction to jeans and a Leal's, and we'll be able to talk Mawr and Maura about these as we talk about my oh sis moving forward in our chapter. So I'll see you all in our next video