A researcher has a laboratory strain of flies that have loss-of-function mutations in both gene X and white.These flies are used as hosts for P element transformation: Embryos of the double mutant strain are injected with two plasmids, one containing a wild-type copy of the white gene (w⁺)and a wild-type copy of gene X, side-by-side within P element inverted repeats, and the other plasmid containing only the P element transposase gene.Transgenic offspring of the injected flies will A)have both plasmids integrated randomly into the genome. B)have white eyes and express transposase. C)have red eyes and a wild-type copy of gene X integrated into a random location in the genome. D)have red eyes and a wild-type copy of gene X in place of the mutant copy in their genome.

Question

Quizplus · Accepted Answer

The P element transformation technique involves integrating a gene of interest (in this case, a wild-type copy of the white gene and gene X) into the fly's genome at random locations using the P element transposase. The transposase facilitates the integration of the DNA within the P element inverted repeats into the fly's genome. Since the injected plasmids contain a wild-type copy of the white gene, the offspring that successfully integrate this gene will have red eyes (correcting the white mutation), and also a wild-type copy of gene X, but these integrations occur at random locations, not specifically replacing the mutant copies.

A Researcher Has a Laboratory Strain of Flies That Have