Go to the OMIM website (http://www.ncbi.nlm.nih.gov/omim...

Question

Go to the OMIM website (http://www.ncbi.nlm.nih.gov/omim) and locate the Search button at the top of the page. Use the Search function to look up, one by one, the following three human hereditary diseases that are relatively common in certain populations: 'Tay–Sachs disease' (select OMIM number 272800 from the search results list); 'cystic fibrosis' (select OMIM number 602421 from the search results list); and 'sickle cell anemia' (select OMIM 603903 from the search results list). For each of these diseases, look through the information and provide the following details:

Briefly describe the disease.

Accepted Answer

Welcome back. Let's look at our next question. It says if an individual affected by a genetic condition, inherited two copies of the mutated gene, one from each parent, then the person is most likely affected by which the following conditions. We look at our answer choices. We have a autism, a dominant condition. B X linked recessive condition, see autism or recessive condition and D none of the above. So let's recall that we do have that none of the above possibility that none of the answers are correct. So we see a person affected by a genetic condition who has to have two copies of the mutated gene, then we know this is a recessive condition. Um If you only need one copy of the mutated gene, then it's a dominant condition. So we can go ahead and eliminate choice a autism all dominant condition since we know it's not dominant. And then now we have to distinguish between choice B X linked recessive condition and autism or recessive condition. Well, the interesting thing is it actually theoretically could be either of these a female with an excellent recessive condition, could express that condition. If she's inherited the affected gene on both X chromosomes, one from each parent, mother and father. However, this is very rare. Um because males only have one X chromosome, they only need one copy of the mutated gene to express the disorder. And therefore, we're going to much more commonly see the case. Um in males with only one x chromosome where the individuals who express the disease or affected by the disease have only one copy of the mutated gene on their single X chromosome. So since our question says, the person is most likely affected by which of the following conditions and autism or recessive condition is much more likely than the excellent recessive condition. So we're going to wear again, the only time you would see it with an individual two mutated copies is in a female. So much more rare than seeing it in males. So we're going to go ahead and eliminate choice B since our, since that's not the most likely case and go ahead and select choice, see autism or recessive condition. And then of course, we can also limit choice D none of the above since we have a correct answer. So again, if an individual affected by a genetic condition inherited two copies of the mutated gene, one from each parent, then the person is most likely affected by which of the following conditions. Choice C autism or recessive condition. See you in the next video.

Key Concepts

Genetic Disorders

Inheritance Patterns

Population Genetics

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