Exam2-key - NAME:_ KEY _ Page 1 (1) [10 Points] The dreaded...

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NAME:______ KEY _______ Page 1 (1) [10 Points] The dreaded sparky phenotype is determined by two X-linked loci, wherein aabb (female) or abY (male) individuals display this hideous phenotype, while all other genotypes at these two loci display the much more attractive Wilbur phenotype. a) In a cross between a sparky female and a Wilbur male, what fraction of the resulting male offspring are sparky ? 100% as all gametes from the female are ab b) Suppose a Wilbur male and female are crossed, and five percent of the male offspring are sparky . What is the genotype (and linkage phase) of the female? 5% of the female gametes are ab= recombinant. Hence female is Ab/aB . c) For the cross in part b), what is the a-b recombination frequency? c/2 = 0.05, or c = 0.10 (2) [15 points ] Sun-devils, like maggots, have no recombination in males. Consider two linked autosomal loci with c = 0.3 in females. Suppose a male Ab/aB sundevil mates with an AB/ab sundevil female. (a) What is the probability of getting an AaBb offspring? Males only give Ab or aB gametes. Hence Pr(AbBb) =Pr(Ab/aB) = Pr(Ab male, aB female) + Pr(Ab female, aB male) = (1/2)(0.3/2) + (1/2)(0.3/2) = 0.15 (b) Now suppose these two loci are sex-linked, with the male now being
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This note was uploaded on 12/09/2009 for the course ECOL UNIVERSITY taught by Professor Walsh during the Spring '09 term at University of Arizona- Tucson.

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Exam2-key - NAME:_ KEY _ Page 1 (1) [10 Points] The dreaded...

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