Genetics 311, Practice problem set 4.

1) Consider the following DNA template strand: 3'TACTATCGAGTC5'
    Give the complementary DNA sequence, the mRNA transcript, and the polypeptide.

Complementary:  5'ATGATAGCTCAG3'
mRNA transcript:  5'AUGAUAGCUCAG3'
Polypeptide:   met - ile - ala - gln

2) An aliquot of 1 x 108 E. coli cells from a strain unable to synthesize arginine, lysine, and serine were plated on complete medium, forming a bacterial lawn.  Replica plates were then made onto minimal medium supplemented by pairs of the three amino acids.  Give the full genotypes of the new mutants.

                                                    arg- lys- ser+                    arg+ lys- ser-

3) A bacterial strain unable to synthesize methionine (met-) was transduced by a strain unable to synthesize isoleucine (ileu-).  Half the resulting broth culture was plated on minimal medium supplemented with isoleucine, the other half was plated on minimal medium alone.  A total of 29 clones appeared on the miminal plates and 320 on the isoleucine plates.  What is the map distance?

Answer: 0.166

4) At time zero a wild-type Hfr strain sensitive to streptomycin was mated to an strep-resistant F- strain mutant at eight loci: a-b-c-d-e-f-g-h-.  Samples were removed at intervals, agitated, and plated on selective media containing streptomycin.  Draw a genetic map from the following results:

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