Biology Forums - Study Force

1. In Drosophila melanogaster, three autosomal genes have the following map:
 


(a) (6 points) Provide the data in terms of the expected number of flies that would be in each of the phenotypic classes below if a female of the genotype a+ b+ c+/a b c (i.e. a+ b+ and c+ are in cis) were crossed to a male of the genotype a b c/a b c. Assume that 1000 flies were counted and that there is no interference in this region. Indicate your answer next to the phenotypic class below:

a+ b+ c+ ________

a b c+ ________

a+ b c ________

a b+ c+ ________

a+ b+ c ________

a+ b c+ ________

a b+ c ________

a b c ________

(b) (6 points) If the cross above were reversed so that the a+ b+ c+/a b c genotype flies were males and the
a b c/a b c genotype flies were females, how many flies would you expect in the same phenotypic classes?
Indicate your answer next to the phenotypic class below:

a+ b+ c+ ________

a b c+ ________

a+ b c ________

a b+ c+ ________

a+ b+ c ________

a+ b c+ ________

a b+ c ________

a b c ________



2. The genome of the fruit fly Drosophila replicates in about 3 minutes. The genome of E. coli replicates in about 20 minutes. Drosophila has about 100 times more DNA than E. coli, and the Drosophila DNA polymerase is about 20 times slower than the E. coli enzyme. How can you explain the faster replication of the Drosophila much larger genome? Answer in 2-3 sentences.

Post Merge: 10 years ago

This is the image of the Drosophila melanogaster gene map

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