PS4+F09+key - Bio D137 Human and Eukaryotic Genetics Prob...

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Bio D137 Human and Eukaryotic Genetics J.L.Marsh F'09 Prob Set 4 due Oct 20 1 3 Point mapping reverse 1. The father of Spock, first officer on the starship Enterprise, is Vulcan. Spock’s mother came from earth. A Vulcan has pointed ears (allele P), adrenals absent (allele A), and heart on the right side (allele R). These 3 loci are linked on the same autosomal chromosome. All these alleles are dominant to earth alleles. The alleles appear as follows: P 25mu A 16mu R If Mr. spock marries an earth woman, what proportion of their children will have (assume no interference): a) Vulcan Phenotype for all three characteristics? b) Earth phenotype for all three characteristics? c) Vulcan ears and heart but earth adrenals? d) Vulcan ears but earth heart and adrenal? Explain the calculations that allow you to arrive at the answers. Answer: (12 points ) Spock’s father is a vulcan, and we assume he is PPAARR. His mother is ppaarr. (we assume this because theses are traits that are not polymorphic for a given species). Therefore Spock is PpAaRr and the woman he marries is ppaarr. She can only give par gametes. Only crossovers in Spock will result in different phenotypes. The possibilities for the children are: i. Result of double crossovers P & R (recombinant): pAr/par or PaR/par – 0.25x0.16=4% (2% each) ii. Crossover between allels P & A (recombinant): Par/par or pAR/par – 25% less 4% that are DCOs = 21 % (10.5% each type) iii. Crossover between allels A & R (recombinant): PAr/par or paR/par – 16% less 4%DCO = 12% SCOs (6% each) iv. Result of no cross over (parental): PAR/par or par/par – 100 –[4+21+12] = 63% (31.5% each) a) For children that are Vulcan for all three phenotypes: 63%/2 = 31.5% (there is an equal probability for PAR/par or par/par). b) Earth for all three – 31.5% c) PaR/par – 2% d) Par/par – 10.5% Grading: lost points if did not divide by 2 when looking for 1 of 2 possible gametes lost points if considered the wrong distance when calculating SCO between P and A (ie 16 mu instead of 25 mu) lost points if did not calculate the RF of DCO correctly lost points if did not substract the RF of DCO (depending on where and how often) lost points if no explanations were given
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Bio D137 Human and Eukaryotic Genetics J.L.Marsh F'09 Prob Set 4 due Oct 20 2 Independent Assortment and Linkage 2. You have two pure breeding strains of rabbits. One strain has brown spots and straight ears (bbSS). The other strain is pure black (no spots) with floppy ears (BBss). Your boss wants you to find out whether the two genes responsible for these traits assort
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PS4+F09+key - Bio D137 Human and Eukaryotic Genetics Prob...

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