Something from nothing: the evolution and utility of satellite repeats.

Large blocks of tandemly repeated sequences, or satellites, surround the centromeres of complex eukaryotes. During mitosis in Drosophila, satellite DNA binds proteins that, during interphase, bind other sites. The requirement for a repeat to borrow a partner protein from those available at mitosis might limit the spectrum of repeat units that can be expanded into large blocks. To account for the ubiquity and pericentric localization of satellites, we propose that they are utilized to maintain regions of late replication, thus ensuring that the centromere is the last region to replicate on a chromosome.