Structure of Ac & Ds elements in maize

    The Ac element includes an Open Reading Frame (ORF1) for a Transposase gene capable of moving the element from place to place in the genome. (The function of ORF2 is unknown). ORF1 & 2 are flanked by non-coding (Nc) inverted repeats. The Ds element is a modified Ac element in which part of ORF1 has been lost and the Transposase gene is non-functional.