INTERSPERSED CENTROMERIC ELEMENT WITH A CENP-B BOX-LIKE MOTIF IN CHIRONOMUS-PALLIDIVITTATUS

Short mobile elements are present in different recombined forms as int erspersed GC-rich islands between AT rich centromeric 155 bp tandem re peats in the dipteran Chironomus pallidivittatus. The basic element is 80 bp long, has a pronounced invert repeat structure and contains a 1 7 bp segment similar to the CENP-B box in mammals. The element inserts into a specific site of the 155 bp repeat in a defined orientation su rrounded by 2 bp direct repeats. The total number per genome of the ma in variant is <20. Elements can be present in all centromeres from C.p allidivittatus and the sibling species Chironomus tentans with pronoun ced differences in distribution within and between species.