summary-questions

Summary Questions

Question 1
Adapted from: Berg JM, Tymoczko JL & Stryer L, Biochemistry (5th Edition), Chapter 6
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.section.5115#5128

Some people are found to have difficulty eliminating certain types of drugs from their bloodstreams. The problem has been linked to a gene X, which encodes an enzyme Y.

Do all the people showing these symptoms have the same problem? To answer this question several people (not related to each other) were tested. Tissue samples from each person were obtained, and

Southern analysis was performed on the DNA after digestion with the restriction enzyme HindIII.
Northern analysis of mRNA also was done.

In both types of analysis, the gels were probed with labeled X cDNA.

A Western blot with an enzyme-linked monoclonal antibody was used to test for the presence of protein Y.

Results for six different people are discussed in this tutorial

Person A is a normal control.
Person B has no symptoms, but some of his children have the metabolic problem.

Persons C through F display the trait.

Here are the results .

Why does person B exhibit no symptoms?

Analyse the problem of person C.

Think, then check the answer.

Analyse the problem of person D.

Think, then check the answer.

Analyse the problem of person E.

Think, then check the answer.

Analyse the problem of person F.

Think, then check the answer.

Question 1 - Summary

A population survey of people who have difficulty eliminating certain types of drugs from their bloodstreams reveals that Gene X may contain several mutations in various locations. These mutations affect differentially the transcription, translation or activity of Protein Y - the product of Gene X. Additional SNPs (single nucleotide polymorphisms) that don't affect function but may serve for detection may also exist.
Below you can see a map of the various SNPs of the ATP-BINDING CASSETTE, SUBFAMILY C, MEMBER 2; ABCC2 in various sites within the gene.

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