A collection of Ac and Ds transposants was generated about a decade ago from a W22 stock carrying the McClintock mutable alleles wx-m7(Ac) and bz-m2(D1) as Ac donor and reporter, respectively. The Ac element is 4565-bp long and encodes an active transposase, so it can be followed phenotypically by its effect on a Ds reporter allele. The Ds2(D1) element is 3253-bp long and arose by internal deletion of the Ac transposase, so it can only be detected molecularly. The collection is made up of roughly 1150 lines carrying a unique transposed Ac element (trAc), obtained by selecting single nonwaxy, spotted (Wx’ , bz-m) exceptional seed from amongst the waxy, spotted parental seed in ears of the wx-m7(Ac) bz-m2(D1) stock. As our subsequent sequencing has revealed, some lines carry, in addition to a trAc, unique transposed Ds2(D1) elements, which can be distinguished from trAc s by the smaller band that they produce in the PCR validation test.
We are sequencing the junctions of the unique transposed Ac elements (tac sites) and Ds2(D1) elements (tds sites) carried in these stocks and have succeeded in placing over 300 of them in one of the ten maize pseudomolecules assembled at Maize GDB. That information, together with the GO description of the gene nearest the element and a rough location of the element with respect to the gene, can be accessed under “ What’s new: Annotated tac/tds Table”. About half of the tac and tds sequences map to chromosome 9, as expected from the chromosomal position of the wx-m7(Ac) and bz-m2(D1) donor alleles. Seed stocks for most sequence-indexed lines are presently available from the Maize Stock Center. The remaining lines are are being increased at Rutgers University in the 2013 Summer and will be sent to the Maize Stock Center next Fall. Lines not presently available from the Maize Stock Center because of limited seed supply can be obtained directly from Hugo Dooner at this time.