Biology Forums - Study Force

A scientist is studying a gene (grn) carried by a bacteriophage that allows a host bacterium to produce a green metabolic product before lysis. The scientist has four bacteriophage mutants for this gene. Mutant 1 has a nonrevertible mutation in grn while Mutants 2, 3, and 4 each have a revertible mutation in grn. After plating pairs of mutants and subsequent coinfection of host cells, the scientist observed the following:

I.	Mutants 1 and 2: no green product

II.	Mutants 1 and 3: very rare green product

III.	Mutants 1 and 4: rare green product

Which of the following is NOT consistent with these observations?

▸ A partial deletion in Mutant 1 overlaps a base-pair substitution in Mutant 2.

▸ Mutant 2 has a base-pair substitution at a different site than Mutant 3.

▸ Mutant 3 has a base-pair substitution at a different site than Mutant 4.

▸ Mutant 1's deletion is closer to the base-pair substitution in Mutant 3 than it is to the base-pair substitution in Mutant 4.

▸ A green product should be observed if coinfection occurs with mutants 3 and 4.

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