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Determining probability of inheriting disease gene

Part I:
Imagine you have a friend who is getting married and plans on starting a family right away. She asks your advice about preconception genetic screening because she is concerned about the chance that her future children could have cystic fibrosis. Her fiancé has a sister that has cystic fibrosis, and she has a cousin who has the disease, although none of her siblings have it.

Launch the Multimedia Player (Go to 'Course Materials' and launch 'Unit 3 Multimedia Course Material') for Unit 3 and go to the 2nd activity called 'Unit 3 DB'.

Use the interactive pedigree in the activity to determine the genotypes of your friend's family members. (One uncle and a cousin are marked as having the disease).

Determine the probability of your friend being a carrier of the disease.

What is the likelihood that if she married this person, her children would inherit cystic fibrosis? Would you suggest she (or any of her family members) undergo genetic testing before starting a family? Why or why not?

Part II:
Briefly describe how genetic knowledge assists us with testing for one specific genetic disorder other than cystic fibrosis. Describe the disorder, genetic tests currently in use, and any potential for gene therapy or possible treatments. Use an authoritative reference to support your points.


Solution Preview

Part 1
I will answer the question based on the information you have provided since requests for the link have not been answered.

Husband's family:
We know that his sister has CF. Because this is a recessive disease both his parents must be carriers.


The possible genotypes from this cross are CC, Cc, Cc, cc. This is a 1/2 chance that the husband is a carrier of the recessive and disease causing allele.

Wife's family:
From the information you have provide it indicates that an uncle and a cousin of the wife have CF.

This means that her uncle's parents (the wife's grand-parents) would have to be CcxCc. That means that there is a 1/2 chance that one of the wife's parent is a carrier. Because I ...

Solution Summary

Examination of Mendelian patterns of inheritance in disease carriers and reproductive strategies (example of cystic fibrosis inheritance is used).