Sample Exam I

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=90 BGCOLOR="#006699" TEXT="#080000" bgproperties="fixed" background="109285a1erlcgo.gif"> <div> <FONT SIZE="5" COLOR="#FFCC66" FACE="Arial" ><B>Human Genetics</B></FONT><B>     |     </B><A HREF="index.htm" TARGET="_top" TITLE="Human Genetics"><U><B>home</B></U></A></div> <div> <A HREF="id36.htm" TARGET="_top" TITLE="Syllabus"><U>Syllabus</U></A>   |   <A HREF="id82.htm" TARGET="_top" TITLE="Journal Club Days"><U>Journal Club Days</U></A>   |   <A HREF="id27.htm" TARGET="_top" TITLE="Journal Guidelines"><U>Journal Guidelines</U></A>   |   <A HREF="id38.htm" TARGET="_top" TITLE="Journal Club Guidelines"><U>Journal Club Guidelines</U></A>   |   <A HREF="id90.htm" TARGET="_top" TITLE="Genetics Education Model Project"><U>Genetics Education Model Project</U></A>   |   <A HREF="id53.htm" TARGET="_top" TITLE="Recessive Inheritance Model"><U>Recessive Inheritance Model</U></A>   |   <A HREF="id98.htm" TARGET="_top" TITLE="figures"><U>figures</U></A>   |   <B>Sample Exam I</B>   |   <A HREF="id62.htm" TARGET="_top" TITLE="Sample Exam II"><U>Sample Exam II</U></A>   |   <A HREF="id63.htm" TARGET="_top" TITLE="Sample Exam III"><U>Sample Exam III</U></A>   |   <A HREF="id78.htm" TARGET="_top" TITLE="Sample Exam IV"><U>Sample Exam IV</U></A></div> <div> </div> </td> </tr><tr> <td valign="top" width=210 BGCOLOR="#FFCC66" TEXT="#080000" background="108d2c00dkelyh.gif"> <bR> </td> <td valign="top" height=390 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <I>Sample Exam I</I></div> <div> <B>Short Answer Questions</B> </div> <div> 1. The phenotype of a heterozygote differs for dominantly-inherited and recessively-inherited disorders.  Please explain in biochemical or enzymatic terms how a normal phenotype is achieved in a heterozygote for a recessive disorder.</div> <bR> <div> 2. A friend of yours has a daughter who has been diagnosed with osteogenesis imperfecta, the dominantly-inherited genetic disorder we've studied.  Neither your friend nor her husband have exhibited symptoms.  What are two explanations for how the daughter can be affected, but neither parent be affected?  <B>Briefly</B> explain.</div> <bR> <div> 3. You find a woman who is a carrier for Leiden Factor V disorder, a recessively-inherited disorder.  She is married to a man who is heterozygous for a different mutation in the same gene.  Both of the mutations are harmful to the protein's function.  How would you counsel this couple about the risk of having a child with this disorder?  Explain briefly.</div> <bR> <div> 4. Many different kinds of genetic mutations have been found including missense, nonsense, deletion, and insertion.  Choose two and briefly describe how they will likely affect the function of the protein encoded by that gene.</div> <bR> <div> <B>Long Answer Questions</B> </div> <div> Choose 3 of the following 4 questions only; if you answer all 4, I will grade the first 3.</div> <bR> <div> 5. A cystic fibrosis mutation in a certain pedigree is due to a single nucleotide change that destroys an <I>Eco</I>R1 restriction site normally found in this position.  Cystic fibrosis is inherited as a recessive genetic disorder.</div> <bR> <div> a. How can you use this information to counsel members of this family as to their carrier status?  Please describe the exact experiment needed.</div> <bR> <div> b. <U>Diagram</U> the results of an experiment that shows at least one carrier, one affected, and one homozygous normal individual.</div> <bR> <div> c. If the mutation had not changed a restriction enzyme site, what is another method could you use to screen members of this family?</div> <bR> <div> 6. You did such a great job helping the curators of Online Mendelian Inheritance in Man to study pedigrees, they asked for your help again.   </div> <bR> <div> a. Predict the mode of inheritance that is consistent with the following pedigree.  </div> <div> Briefly explain your reasoning.  </div> <bR> <div> <IMG SRC="0c1c9e40.gif" border=0 width="457" height="228" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <bR> <div> b. Note the genotype for each individual.</div> <bR> <div> I-1:  <U>                    </U></div> <div> I-2:  <U>                    </U></div> <div> I-3:  <U>                    </U></div> <div> I-4:  <U>                    </U></div> <div> II-1:  <U>                    </U></div> <div> II-2:  <U>                    </U></div> <div> II-3:  <U>                    </U></div> <div> II-4:  <U>                    </U></div> <div> III-1:  <U>                    </U></div> <div> III-2:  <U>                    </U></div> <div> III-3:  <U>                    </U></div> <div> III-4:  <U>                    </U></div> <div> III-5:  <U>                    </U></div> <div> III-6:  <U>                    </U></div> <bR> <div> c.  Briefly explain why you think the pedigree is not consistent with the “other” mode of inheritance (not the one you chose in part a).7. Somatic cell hybrid cell lines were tested for the presence of a series of human enzymes, LDH, 6GPGD, and PGK.  From the results given in this table determine the chromosomal location of each human gene.  Briefly explain your reasoning.</div> <bR> <div> <B>Cell</B></div> <div> <B><U>Line</U></B><B>     </B><B><U>         Human Chromosomes Present     </U></B><B>     </B><B><U>LDH          6GPGD     PGK</U></B></div> <div> <U>     3     6     9     12     17     22                              </U></div> <div>  </div> <div> A     +     +     +     -     +     -     +          +          +</div> <div> B     -     -     -     -     +     +     +          -          -</div> <div> C     +     +     -     -     -     -     -          +          +</div> <div> D     +     -     -     +     -     -     -          +          +</div> <div> E     -     +     +     +     -     -     -          -          -</div> <div> F     +     -     -     -     +     +     +          +          +</div> <bR> <div> a. LDH</div> <bR> <div> b. 6GPGD</div> <bR> <div> c. PGK</div> <bR> <div> 8. You want to study the newly discovered gene for aging.  To clone this gene you cleave genomic DNA and vector (plasmid) DNA with the restriction enzyme Pst I.  Your gene of interest is contained on a 3000 base DNA fragment and your vector is 5000 bases. You put these DNAs in the same tube and add ligase to join them together.</div> <bR> <div> a.  Diagram the plasmid with the gene of interest incorporated into the vector.  Be sure to label the restriction enzyme sites and note the relative sizes in bases.</div> <bR> <div> b. You know that not all vectors will have incorporated your gene of interest.  Design an experiment that will allow you to tell which vectors contain your gene of interest and which ones do not contain your gene of interest.</div> <bR> <div> c. <U>Diagram</U> the results of the experiment that you would expect for both types of plasmids (no gene of interest cloned, gene of interest cloned).</div> <bR> </td> </tr></table></body>