The following diagram shows a cell in meiosis. Identify the stage of meiosis shown.

Question

Diagram illustrating chromosomes during Meiosis I, showing homologous pairs and crossing over.

Accepted Answer

Welcome back everyone. Let's look at our next problem. During the recombination. In the pro face stage DNA sequences are broken and then rejoined, identify which of the genetic recombination will occur after the crossing over of the given homologous pair. So here we see our pair of homologous chromosomes, say paternal and maternal. And we see in this spot, right here on the inner legs where they were next to each other in our arms, the lower arms you have a crossing over point. So what we'd expect to see is at this point right here on the lower parts of these arms, below the crossing over point. We're going to see an exchange of that piece of chromosome and we'll see that swapped. So now I'm going to scroll down just to show us all of our answer choices here so we can evaluate them. So this gives us four possibilities for what the chromosomes will look like after that crossing over. So let's look at choice A choice A shows the outer arms of the lower part of these two chromosomes with the piece swapped, but it's the inner arms that that have crossed over. So choice A is not correct. Now let's take a choice B. Choice B does show we're on the inner arms were down on the lower arms. And we see that yes, that lower portion there below the crossover point has swapped. Now the two chromosomes each have a little bit of the homologous chromosome from the other parent. So Choice B does correctly show what has happened and what those chromosomes look like after recombination. But let's just take a look at our other choices just to see why they are not correct. We see choice. See here, Choice C. Has the swapped portion occurring above the crossing over point, but that is not correct. It's down below the crossover point or more outer. If the crossing over point, we're up here, the crossover portion would be above. So further away from the center mears is where that those pieces swap. Then Choice D. Indeed shows at the end of the arms correctly, but it's chosen on the upper arms of that pair. So Choice D. Is incorrect. So again, our correct answer is Choice B. For representing what those chromosomes will look like after recombination. See you in the next video.

The following diagram shows a cell in meiosis. Identify the stage of meiosis shown.

Verified video answer for a similar problem:

Key Concepts

Meiosis

Crossing Over

Homologous Chromosomes