137+MT+Fall+111107+wKey

137+MT+Fall+111107+wKey - BIO D137 2011 EUKARYOTIC GENETICS...

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Unformatted text preview: BIO D137 2011 EUKARYOTIC GENETICS MID TERM EXAM November, 2011 There are 5 parts to this exam. Everyone should answer all parts. Present your answers in a legible form. If you believe that you have more information about a problem than was covered in class or the reading or than is stated in the question, and if you believe your additional knowledge makes the question ambiguous, you should mention the facts in question, reference your source and proceed with the question. (20 points) I ______________ (20 points) II ______________ (20 points) III ______________ (20 points) IV ______________ (20 points) V ______________ TOTAL ___________________ NAME ___________________ STUDENT NUMBER WARNING: Put your name or number on each sheet including scratch sheets. The most common reason for loss of points is not showing your reasoning in detail. Do not leave it to me to infer whether you understand the problem, defend the logic of your answer. REGRADES NOTE: If we made a mistake, requests for regrades must be submitted in writing with an explanation of why the assigned grade was not correct and should be different. Last day to submit regrades is Wednesay Nov 23 rd @ 4pm in the drop box. Bio 137 Mid term 2011 Name:_________/ Student #:________ 2 1] The following pedigree illustrates the inheritance of Nance-Horan syndrome, a rare genetic condition in which affected persons have cataracts and abnormally shaped teeth (see photo). a. Based on the pedigree, determine what you think is the most likely mode of inheritance and explain your case. Answ: 4pts This is X linked recessive because only males show it & they seem to pass it on through their daughters as carriers because it reappears in their grandsons. Autosomal recessive is unlikely because of the generation skipping and because this pedigree would require 6 out of 6 people marrying into the family to be carriers of this rare trait Dominant is less likely because we would have to invoke several cases of incomplete penetrance. 1pt for recessive, 2 for sex linked, 1 for argument. b. Couple III-7 x III-8 are contemplating having another baby. They have asked you what the probability is that their next child will have Nance-Horan syndrome? Tell them the probability and explain how you arrived at it. Answ: 6pts We know that III-7 is a carrier of this X linked trait. If she has a girl, the chances are 0% that it will be affected (or very very small because the carrier freq is small in the population) and if she has a boy (50% chance), the chances are 50% for him to be affected so the chance that the next child will be affected is 1/2 x 1/2 = 1/4 (25%). 3 pts argument, 3 pts for 25% c. If III-2 & III-7 have a child together, what is the probability that any child they had would have Nance-Horan syndrome? Bio 137 Mid term 2011 Name:_________/ Student #:________ 3 Answ: 4pts – 2pts for correct answer, 2pts for argument or punnett square. We know that III-7 is a carrier of this X linked trait because her father exhibited the disease...
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This note was uploaded on 12/13/2011 for the course BIOSCI 137 taught by Professor Staff during the Fall '11 term at UC Irvine.

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137+MT+Fall+111107+wKey - BIO D137 2011 EUKARYOTIC GENETICS...

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