A woman who sought genetic counseling is found to be heterozygous...

Question

A woman who sought genetic counseling is found to be heterozygous for a chromosomal rearrangement between the second and third chromosomes. Her chromosomes, compared to those in a normal karyotype, are diagrammed to the right.

Using a drawing, demonstrate how these chromosomes would pair during meiosis. Be sure to label the different segments of the chromosomes.

Accepted Answer

Hey everyone. Let's take a look at this question together. Non disjunction happens when there is a failure of homologous chromosomes or sister chroma tides to separate during mitosis. Which of the following is a consequence of non disjunction. So we know that non disjunction is the failure of those homologous chromosomes or the sister chroma tides to separate during mitosis. So when we have that failure two separate, that lack of separation can lead to chromosome duplication or even the loss of whole chromosomes. And because of that duplication or loss, we end up with errors in the number of sets of chromosomes. So we have an incorrect number of sets of chromosome pairs. And so, looking at our answer choices which best represent those consequences of non disjunction. Well, answer choices A and B. Both say duplication and loss. Which we know is true and answer choice C says that incorrect number of chromosome sets, which we know is also true. So that would mean that the best option here is answer choice D. All options are correct. Which is the correct answer because we know that when we have non disjunction, which is that failure of those chromosomes or sister chromatis to separate during mitosis. We end up with chromosome duplication and loss which then can lead to an incorrect number of chromosome sets. So answer choice D. Best represents that and is the correct answer to this question. I hope you found this video to be helpful. Thank you and goodbye

Key Concepts

Heterozygosity

Meiosis

Chromosomal Rearrangement

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