Figure 1.

Origin and structure of γ1230. γ1230 was generated by radiation-induced deletions of Dp8–23(Le et al. 1995). The positions of the “islands” of complex DNA (Tahiti, Moorea, Bora Bora, and Maupiti) are shown, as is the position of the new euchromatin/heterochromatin junction (“breakpoint”). The 420-kb functional centromere was localized by examining the transmission behavior of a large collection of minichromosome derivatives (Murphy and Karpen 1995b). Restriction mapping and hybridization analysis indicated that the centromere portion of γ1230 contained two satellite DNA blocks (AATAT and AAGAG), five small islands of complex DNA (Motus) inserted into the AATAT block, and a large region of complex DNA (Maupiti) at the right end (Sun et al. 1997). The sizes of the satellite blocks are shown.