Transcription of 'junk' DNA acts as a master switch that prevents male-producing sperm from dying during development.
April 1, 2026
Original Paper
Defective transcription of AAGAG satellite DNA causes sex-ratio meiotic drive in Drosophila
bioRxiv · 2025.01.10.632443
The Takeaway
Scientists found that a specific type of repetitive satellite DNA—long thought to be useless—must be active to package sperm DNA. When it fails, Y-chromosome sperm die off preferentially, revealing a bizarre molecular mechanism that can naturally skew the ratio of male to female births.
From the abstract
Male germ cells have complex transcriptomes, with a large fraction of the genome being transcribed. This includes protein-coding genes (often not translated), non-coding DNA, and repetitive DNA, such as transposons and satellite DNA, which are normally silenced as heterochromatin. The significance of such widespread transcription remains unknown. Here, we show that a heterochromatin protein, HP2, is required for the transcription of AAGAG satellite DNA in Drosophila spermatocytes. HP2 depletion