A number of experiments have demonstrated that areas of the genome that are transcriptionally inactive are also resistant to DNase I digestion. However, transcriptionally active areas are DNase I sensitive. Describe how DNase I resistance or sensitivity might indicate transcriptional activity.

Video transcript

Hi everyone. Let's look at our next problem. It says D. N. A. Is a nucleus that can cleave the D. N. A. On its ends. The type of D. N. A. Ends in which one strand is longer than the other. Leaving uncared bases is referred to as well. So let's just envision here um A. D. N. A. Strand where we have our um two complementary strands. So I've put up a little shorter sequence here. And if we imagine our D. N. A. D. N. A. Cleaning this D. N. A. Say right here, That kind of cleavage, we're gonna be left with the c. g. g. c. one part of the D. N. A. And there's other two strands on the other part of the DNA. But all the bases here will be paired. And when we do that kind of cleavage the ends here. So this where we'll have A D. N. A. Strand that comes along ending like that. And then another D. N. A. Strand that comes along ending. Like this. Those are called blunt ends. But there's another kind of cleavage that this is asking us about where we have one strand longer than the other. So let's envision that. So now we're gonna envision DNA cleaving our D. N. A. Like this and in that case our ends are going to look different. One will be longer than the other. Our strand on the left will look like this with these two base pairs here sticking out as the rest of our strand. And then our strand over here is going to have an end that looks like this. So again one end longer than the other. These two remaining unpaid aired. This is useful. These are called sticky ends and it's useful because we can use this to put DNA pieces together. If we cut to different types of DNA, we want to slice together with one of these enzymes. We will have a complimentary ends and you could have another um another part piece of DNA. That ends and was cut in a similar way and it will stick together with this other one. Thus the sticky ends. So when we look over at our answer choices, we can go ahead and eliminate choices. C. And D. Regular ends and random ends as they're not a term for what's going on here with our DNA is cutting the D. N. A. And we know that choice. A blunt ends is not correct because that's the ends. When both um D. N. A. Strands are the same length, there's no unpaid basis. But what we have is choice be sticky ends where we leven paired bases behind. So that type of D. N. A. Ends where one strand is longer than the other choice. Be sticky ends. See you in the next video