bk1 << p1:bk1 << p1:bk2 << bk2
Dp(1;f)γ878/Dp(1;f)γ1230 heterozygotes increases y+ expression, to 27% of full Dp(1;f)γ158 trans-suppression - relative suppression. y+ expression is quantitated in triple row bristles.
700kb deletion of centric heterochromatin and euchromatin including the y+ gene region.
Monosome transmission behaviour from both male and female parents is stable demonstrating normal transmission and normal centromere function.
Used in experiments that showed that efficient achiasmate homolog disjunction in female meiosis I requires 1000kb of overlap in the centric heterochromatin and is not affected by homologous euchromatin or overall size differences. Disjunction efficiency decreases linearly as heterochromatic overlap is reduced from 1000 to 430kb. Rescue experiments with nod transgenes showed that heterochromatin does not act solely to promote chromosome movement or spindle attachment. Centric heterochromatin seems to contain multiple pairing elements that act additively to initiate or maintain the proper alignment of achiasmate chromosomes in meiosis I.
Interstitial deletion.
700kb deletion between position -121 in the euchromatin to position +580 in the heterochromatin of the Dp(1;f)1187 derivative Dp1187-8-23, where position 0 is the In(1)sc8 inversion breakpoint. Resulting in a 620kb minichromosome.