The Odom laboratory studies interdisciplinary questions bridging genetics, genome regulation, cancer biology, and evolution. In this talk, I will be providing a brief retrospective of our past 20 years of discoveries in genome evolution, along with related recent and unpublished stories. I will discuss the extensive and rapid turn-over of tissue-specific transcription factor binding, CTCF insulator elements, polymerase occupancies, and enhancer activities among mammalian species – as well as the mechanisms underlying this regulatory plasticity. I will present the unexpected impact that active repeat sequence expansions have in remodelling CTCF-controlled insulator repertoire among diverse mammals. To demonstrate that genetic sequences were the major determinant of transcription and transcriptional regulation, my lab re-purposed an aneuploid mouse model that carries a copy of human chromosome 21 as an elegant and powerful demonstration that cis-acting sequences have a greater impact than trans-influences on transcription factor binding, chromatin state, and gene expression. We have exploited the power of single-cell transcriptomics to identify that an increase in cell-to-cell variability is a key hallmark of age-related functional decay in primary mammalian tissues. Most recently, we have used chemical carcinogenesis to study the earliest steps of tumour genome evolution and clonal expansion, as well as the conservation of these mechanisms across mammalian space. We and our collaborators recently discovered lesion segregation, a mechanism shaping the genome of all mammalian cells exposed to DNA damage.