Final answer:
The Drosophila-specific transposon referred to in the question is the P element, which is capable of moving within the DNA and influencing gene expression.
Step-by-step explanation:
The specific Drosophila-specific transposon that the question refers to is the P element. Genetic elements like the P element are known as transposons and are often described as "jumping genes" because they can change position within the DNA of an organism. Transposons like the P element are distinct from Ac and Ds elements found in maize, which were discovered by Barbara McClintock. Although transposons were originally identified in maize, they have since been found in a wide array of organisms, including Drosophila. They carry inverted repeat sequences and a transposase enzyme, enabling them to move from one genomic location to another, which can influence gene and protein expression and the organism's phenotype. T
he Ac element is needed to mobilize both itself and the Ds element by providing the transposase; however, the P element is a Drosophila-specific transposon capable of mobilization on its own. Transposons are crucial for introducing genetic diversity within genomes and have been a part of life for a long evolutionary period.