Final answer:
The assertion that Ds elements are longer than Ac elements due to insertions is false. Length differences between these transposable elements are related to their genetic content, specifically the presence or absence of the gene for transposase, rather than the process of insertion.
Step-by-step explanation:
The statement that the Ds elements are longer than Ac elements due to insertions is false. Both Ds and Ac elements have eleven bp inverted repeats at their ends, and insertions cause eight bp direct repeats of the target DNA. The length differences between Ds and Ac do not stem from insertions; rather, Ds elements lack the gene for the transposase enzyme required for transposition, while Ac elements contain this gene and can hence transpose independently. The length of transposable elements, such as Ds and Ac, is determined by the genetic content and structural features, not necessarily by the process of insertion.
Barbara McClintock's discovery of these mobile genetic elements in maize, like Ds and Ac, led to the Nobel Prize in Physiology or Medicine in 1983. Understanding how these elements can activate, insert, and potentially disrupt other genes provides insight into genetic regulation and variability. Furthermore, the ability of Ac to provide the transposase needed for its own mobility as well as for the Ds element exemplifies the interactive nature of these transposable sequences.