BICD100_FA05_FinalKey

BICD100_FA05_FinalKey - FINAL EXAM ANSWER KEY BICD100...

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FINAL EXAM ANSWER KEY BICD100 GENETICS FALL 2005 PROF. REINAGEL class statistics at end QUESTION 1 TOTAL POINTS: 6.5 PARTS: a – g 1. In an experiment like Mendel's, true-breeding plants with flat flower petals were crossed with true-breeding plants with ruffled flower petals. The F1 generation plants had ruffled flower petals. You allow F1 plants to self- pollinate to form a second generation, and analyzed the seeds of the resulting F2 generation. a. Assign your symbols (½ pt) Dominant allele: A phenotype: ruffled Recessive allele: a phenotype: flat b. What is the genotype of the F1 plant? Aa (½ pt) c. What types of gametes does the F1 plant produce, in what ratio? 1 A : 1 a (½ pt) d. What are the genotype s of the F2 generation plants, in what ratio? 1 AA : 2 Aa: 1 aa ( ½ p t ) e. What are the phenotypes of the F2 generation plants, in what ratio? 3 ruffled : 1 flat ( ½ p t ) f. Two genotypes of F2 plants have the same phenotype. To which of the pure breeding parental plants should you cross them to tell them apart? What ratio of phenotypes do you expect in the resulting progeny in each case? Genotype of the parent to which you will cross: aa (½ pt) For F2 plants with genotype ____Aa__ expect progeny phenotypes in ratio 1 ruffled: 1 flat (½ pt) For F2 plants with genotype ___AA__ expect progeny phenotypes in ratio 1 ruffled : 0 flat (½ pt) Page 1of 16
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g. In your actual experiment you obtained 184 ruffled + 40 flat-petaled F2 plants. Use a Chi Square test to determine whether the observed data ARE CONSISTENT WITH Mendel’s predicted ratio, with a confidence threshold of 0.05. Show your work and put a box around the χ 2 value, the P value, and your yes/no answer below. (2 ½ pts) O E (O-E) 2 (O-E) 2 /E 184 168 256 1.524 40 56 256 4.571 Chi square ( χ 2 ) = 6.095 Df= 2-1=1 0.05>P>0.025 Circle one: YES the data are consistent with the predicted ratio NO the data are significantly different from the predicted ratio Partial credit on chi square test: ½ pt for correct obs and exp values ½ pt for correct chi square value ½ pt for correct df ½ pt for correct p value ½ pt for circling “no” Page 2of 16
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QUESTION 2 TOTAL POINTS: 6.0 PARTS: a – c 2. Wild-type fruit flies have brown bodies and red eyes. You have a pure- breeding yellow-bodied strain of flies (otherwise normal), and another pure- breeding strain of flies with peach-colored eyes (otherwise normal). The allele for yellow-body is recessive to the allele for brown-body, and the allele for peach- eyes is recessive to the allele for red-eyes. You cross males from the yellow- bodied strain to females from the peach-eyed strain to obtain an F1 generation. a. You cross the F1 flies to one another and analyze the F2 progeny. If everything is working the way Mendel predicted for a simple dihybrid cross with independently segregating traits, what phenotypic classes do you expect to find, and in what ratios? (Simply list the possible phenotypes and state the relative frequencies). 9 Brown Red: 3 Brown peach : 3 yellow Red : 1 yellow peach
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This note was uploaded on 04/08/2008 for the course BICD 100 taught by Professor Nehring during the Fall '08 term at UCSD.

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BICD100_FA05_FinalKey - FINAL EXAM ANSWER KEY BICD100...

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