The human genome contains approximately 10⁶ copies of an Alu sequence, one of the best-studied classes of short interspersed elements (SINEs), per haploid genome. Individual Alu units share a 282-nucleotide consensus sequence followed by a 3'-adenine-rich tail region [Schmid (1998)]. Given that there are approximately 3 x 10⁹ base pairs per human haploid genome, about how many base pairs are spaced between each Alu sequence?

Video transcript

Everyone. Welcome back. Let's look at our next question. It says which of the following transpose herbal elements does not exist in the human genome. So let's look through our answer choices here. Choice A. Is ALU A. L. U. Um This is found in the human genome. So we're going to eliminate that. It's actually um One of the most abundant transpose transposing elements found in humans. It comprises about 11% of the human genome. And it's a primate specific. Let's move on to our next choice. Which is choice b. l. one. Um This is another one found in humans so not our answer. It's a retro transpose on also known as Line one. L. I. N. E. One. Um it's also very abundant. Even more so so than the Alu transpose on um comprising about 17% of the human genome. So it's pretty incredible when we think about how much the genome is made up of these transfusions. Um L. One is implicated in diseases like cancer in that if these um transpose insert in the middle of genes that can disrupt the function of the gene choice C. Is S. V. A. And these are also found in humans. So we can eliminate them. Another retro transpose on oops and also implicated in diseases when it inserts into genes and disrupts their expression. So finally we're down to choice D. The P. Element and that is our answer. The P element is a transpose on found in fruit flies. Good old good old Drosophila. So that's not a human transpose on but something in the fruit fly. So and this is associated with its use as a tool to create mutants in a controlled way in Drosophila. So we actually use the P element uh in genetic studies. So again, which of the following transportable elements does not exist in the human genome choice D. P. Element. See you in the next video.