Understanding the regulatory mechanisms that shape gene expression after transcription remains one of the central challenges in molecular biology. In the context of the ERC Synergy project EPIC, our team aims to unravel the eukaryotic post-transcriptional code by generating a comprehensive map of post-transcriptional regulation across evolutionary time. Focusing primarily on Saccharomyces cerevisiae, we will investigate post-transcriptional dynamics under 10 distinct environmental and cellular conditions using an integrative toolkit including Smart-seq, SLAM-seq, 5PSeq, and whole-genome sequencing. Expanding the phylogenetic breadth, we will further profile ~100 additional eukaryotic species under two matched conditions, covering a wide evolutionary span. Our goal is to accurately and efficiently map transcription start sites (TSS) and polyadenylation sites (PaS) across these species, generating a foundational dataset for decoding the logic of post-transcriptional regulation. Alongside, we are actively developing and benchmarking novel computational and experimental methods to improve accuracy and scalability of such mappings. This project will not only deepen our understanding of gene regulation but also shed light on the evolutionary constraints and innovations in post-transcriptional control.