bk1 << p1:bk1 << p1:bk2 << bk2
The presence of a second minichromosome significantly suppresses terminal deficiency-associated y PEV, this is termed 'trans-suppression'. Trans-suppression does not involve cross-homologue communication between transcription regulatory elements (transvection), nor is it accomplished by titration of heterochromatic factors through the addition of extra centric heterochromatin. Data indicates trans-suppression requires structural homology between two minichromosomes, suggesting pairing is required.
Transmission rate through females to progeny is 54% in the first 5 days of egg lay.
Acentric mini-chromosomes are lost at a moderate but elevated rate during male germline mitotic divisions and in female mitosis, but appear to be transmitted efficiently through pre-blastoderm mitoses and male meiosis. mit(1)15 can localise to the mini-chromosome.
Large inversion of centric heterochromatin, one breakpoint located just distal to y and the other within centric heterochromatin.
Monosome transmission behaviour from both male and female parents is stable demonstrating normal transmission and normal centromere function.