As mentioned in Section 9.3, mtDNA accumulates mutations...

Question

As mentioned in Section 9.3, mtDNA accumulates mutations at a rate approximately ten times faster than nuclear DNA. Thus geneticists can use mtDNA variations as a 'molecular clock' to study genetic variation and the movement of ancestral human populations from Africa to different areas of the world more than 125,000 years ago. Propose an explanation for how an analysis of mtDNA can be used to construct family trees of human evolution.

Accepted Answer

Welcome back everyone. Here's our next question which of the following states the reason the mitochondrial DNA experiences more frequent mutations compared to nuclear D. N. A. So let's walk through our options here recalling that when we look at them over Choice D. Has all options are correct. So we could have more than one correct answer. Choice A says the mitochondria contain reactive oxygen species. Well this is correct. Uh due to cellular respiration, there is the presence of these reactive oxygen species in mitochondria that are highly mutagenic and toxic. So this is definitely a reason that there's more mutation to D. N. A. To mitochondrial D. N. A. So I'm going to mark this is correct but not choose it as our answer because of the potential that we have for all the options being correct. Choice B says the mitochondrial D. N. A. Does not have structural protection. Well this is also correct. Um There's no his stones present in mitochondria and so therefore they're lacking that extra structural protection that his stones provide in nuclear DNA. So Choice B is also correct. If I wanna test, I wanted to move quickly. I'd go ahead and choose at this point, Choice D all options are correct. Since I already have more than one correct answer. But here we're gonna be thorough and go also to choice C. Which says the mitochondrial DNA has limited DNA repair mechanisms and this is indeed also correct, mitochondrial DNA doesn't have all the many ways of repairing DNA changes that nuclear DNA does. It pretty much only has basic decision repair as its only method. Who does have that limited amount of repair mechanisms for DNA mutations, but not the multi pronged approach that nuclear D. N. A. Has. So again, which the following states the reason the mitochondrial DNA experience more frequent mutations compared to nuclear D. N. A. Choice D. All options are correct reactive oxygen species. No, his stones and limited DNA repair mechanisms. See you in the next video.

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