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.

This woman is phenotypically normal. Does this surprise you? Why or why not? Under what circumstances might you expect a phenotypic effect of such a rearrangement?

Accepted Answer

Hi, everyone. Welcome back. Let's look at our next question. It says sickle cell anemia is caused by mutation of a single nucleotide in the beta globe and JEAN, which of the following triggers the expression of this disease. So this is asking us which sort of gene status. When we look at our answer, choices causes the disease to be expressed, the person to show symptoms, be affected by this disease. Um We should notice that choice D is none of the options is correct. So just keep in mind that's an option. And let's look at our answer choices. Choice A says homocide gossipy for the unaffected beta global gene. Well, being homeless, I guess having to unaffected genes obviously does not trigger the expression of the disease because you do not have any sickle trait cells. You have two normal healthy versions of the gene. Choice B says hetero Zigong City for the Beta Globe and gene um hetero zig. It's for this gene do have some of their cells prone to cycling because half of their beta globe and protein is that mutated form. So under low oxygen conditions, some of those red blood cells will form that sickle shape. However, since half of the protein they produce is normal and healthy, they're not prone to those same vaso inclusive crises that people who are Homo Ziegesar. So they generally don't suffer from symptoms of the disease. So this would not be our answer because hetero cigarettes don't express the disease in terms of suffering from its symptoms. Choice. C says homocide gossipy for the affected beta globe and gene and this is correct. Um Those that are homeless, I guess all of the Beta globe and protein they make has this changed amino acid that causes the blood cells to sickle under oxidative stress and causes these painful health crises and other associated problems. So that essentially makes this a recessive valuable in the sense that you don't suffer from symptoms unless you have two copies of the gene, even one normal copy is enough to prevent the expression of that disease. So we can also eliminate obviously, choice d none of these options is correct since choice C is correct. So we'll go ahead, eliminate that. And again, which of the following triggers the expression of sickle cell disease. Choice C homocide. Gossipy for the affected Beta globe and jean. See you in the next video.

Key Concepts

Heterozygosity

Chromosomal Rearrangement

Phenotypic Expression

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