CHROMOSOME LABELING WITH TRANSPOSABLE ELEMENTS IN MAIZE

Transposable elements randomly insert into a targeted locus at a frequ ency of 10(-6) to 10(-5). The En element has been shown in previous st udies to transpose more frequently into closely linked sites. Thus, it is appropriate to place an En element onto each of the 20 chromosome arms in maize to maximize tagging efficiency. This is called chromosom e labeling for tagging purposes with transposons. After a chromosome a rm has been labeled with a transposon, genes residing in that arm will have a greater chance to be tagged by the transposon. To date, all of the maize chromosome arms have been labeled with at least one of five Encontaining alleles. The elements were linked to the arms using reci procal translocations. The usage of these arm-labeled lines is discuss ed in the context of gene tagging.