The birth, death, and evolutionary compensation of uORFs in Drosophila

Upstream open reading frames (uORFs) are critical regulators of messenger RNA translation, yet their evolutionary dynamics remain poorly understood. Here, we analyze uORF evolution across Drosophila species and uncover pervasive birth-death turnover. This process is characterized by a persistent excess of upstream start codon (uATG) gains over losses, shaped by the interplay of mutational input and natural selection. We find that the evolutionary conservation of uATGs is strongly associated with