Two Independent Mutants Are Discovered in a Strain of Fruit

question 51

Multiple Choice

Two independent mutants are discovered in a strain of fruit flies. Both are due to the insertion of a transposable element into a gene that is required to produce red pigment in the eyes, but the eyes are yellow instead of red. When the transposon undergoes transposition to another location, the copy present in the original location is sometimes deleted. When the copy in the gene required for red pigment is deleted, the gene regains its ability to function, and the cell with the deletion and all its descendants can produce the red pigment. In one mutant, A shown below, the eyes have tiny red sectors scattered throughout, whereas in the other mutant, B, the eyes have larger blotches of color. What do these patterns tell you about the transposition of the transposons in the mutants A and B?

• A)The transposons in A and B transpose at about the same time in development.
• B)The transposon in A tends to transpose at an earlier time in development than that in B.
• C)The transposon in A tends to transpose at a later time in development than that in B.
• D)The transposon in A is likely a retrotransposon, which in B is a DNA transposon.
• E)The transposon in A is likely a DNA transposon, which in B is a retrotransposon.

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Definitions:

Fingertips

The extreme ends or tips of the fingers, sensitive to touch and important for fine motor skills.

Laceration

A deep cut or tear in the skin or flesh, often requiring medical treatment to prevent infection or further injury.

Body Tissue

Groups of cells that perform a similar function in the body, such as muscles, nerves, and epithelium.