The IR-1 repetitive family. The F18E3 insert structure is depicted. Note that the IR-1 element is located adjacent to a potential gene, F18E3.2, whose predicted exons are shown as black boxes. Additional IR-1 element copies are diagrammed below. Five full-length copies 379 bp in length were identified (in cosmids F18E3, R07D5, F08G5, C17C3, and C04E7). Two truncated copies (F52H3 and F22B7) and three unusual copies (F47E1, F45E1, and DH11) were also identified (see also Table 1for additional copies). The 15-bp A modules and the 143-bp B modules are indicated along with the sizes of the various regions, including the 2-bp flanking duplications (small black boxes). Note that F52H3 contains an entirely different spacer sequence (black rectangle).
