Luchi8115
Luchi8115
05.11.2019 • 
Biology

In your research on amino acid biosynthesis in e. coli, you have identified three new auxotrophic mutants in a mutagenesis screen. each mutant can grow on minimal medium only if it is supplemented with a specific amino acid, as follows:
lys2 mutants require lysine.
gly3 mutants require glycine.
phe1 mutants require phenylalanine.
as part of your research, you decide to map the locations of the three mutant loci.

to make a rough map of the lys2, gly3, and phe1 loci, you perform an interrupted conjugation experiment between the following two strains:
hfr lys2+ gly3+ phe1+ amps × f- lys2- gly3- phe1- ampr
(note: amps indicates sensitivity to ampicillin. ampr indicates resistance to ampicillin.)
you interrupt conjugation after 1 min, 2 min, and 3 min and plate exconjugants on minimal medium containing ampicillin and various combinations of lysine, glycine, and phenylalanine. you then score the resulting plates for the presence of colonies.
based on the results shown below, what are the possible genotypes of the colonies that grew on each medium? answer the question by dragging one pink label to each pink target, one white label to each white target, and one blue label to each blue target. labels may be used once, more than once, or not at all.

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