Exact breakpoints of the In(1)wm4 rearrangement

Abstract

In(1)w m4 has been known for decades as a classic example of a position effect variegation-causing rearrangement and has been mentioned in hundreds of publications. Nevertheless, its euchromatic breakpoint has not been localized with base-pair resolution. We performed nanopore sequencing of DNA from In(1)w m4 homozygous flies and determined the exact position of euchromatic (chrX:2767875) and heterochromatic breakpoints of the rearrangement. The heterochromatic breakpoint is located in an unlinked part of the genome in the region, enriched in TEs (transposable elements) fragments. A set of unique piRNAs could be detected in the region.