Final answer:
The Ds element is a transposable element, known for causing chromosome breakage in maize when activated by an Activator (Ac) element. It lacks its own transposase enzyme but can be mobilized by the transposase produced by the Ac element, leading to genetic changes such as deletions and translocations that can affect gene expression.
Step-by-step explanation:
The Ds element, also known as the Dissociator element, is a type of transposable element or transposon identified in maize (corn) by Barbara McClintock. It is known for its involvement in chromosome breakage. The Ds element itself cannot cause chromosome transposition (movement) since it lacks the gene for the transposase enzyme, which is required for cutting and pasting the element into a new location within the genome. However, when the Activator (Ac) element, which has the transposase gene, is present in the genome, it can mobilize the Ds element, leading to chromosome breakage and potential alterations in gene function. This can result in visible changes, such as the variegated color patterns on maize kernels due to the Ds element interrupting pigment-producing genes.
Through McClintock's research, which later earned her the Nobel Prize, it was clarified that transposons are significant genetic elements that contribute to genetic diversity and evolution. They can cause mutations, vary gene expression and are integral to the understanding of genetic regulation and chromosomal structural changes like deletions and translocations.