An intricate molecular machinery is at the core of gene expression regulation in every cell. During the initial stages of organismal development, the coordinated activation of diverse transcriptional programs is crucial and must be carefully executed to shape every organ and tissue. Bivalent promoters and poised enhancers are regulatory regions decorated with histone marks that are associated with both positive and negative transcriptional outcomes. These apparently contradictory signals are important for setting bivalent genes in a poised state, which is subsequently resolved during differentiation into either active or repressive states. We discuss the origins of bivalent promoters and the mechanisms implicated in their acquisition and maintenance. We further review how the presence of bivalent marks influences genome architecture. Finally, we highlight the potential link between bivalency and cancer which could drive biomedical research in disease etiology and treatment.

中文翻译：

---

二价基因组：表征，结构和调控。

复杂的分子机制是每个细胞中基因表达调控的核心。在有机体发育的初始阶段，多种转录程序的协同激活至关重要，必须小心执行以塑造每个器官和组织。二价启动子和平衡增强子是用组蛋白标记修饰的调节区，组蛋白标记与阳性和阴性转录结果均相关。这些明显矛盾的信号对于将二价基因设置为平衡状态非常重要，该平衡状态随后会在分化为活跃状态或抑制状态时被解析。我们讨论了二价启动子的起源以及涉及其获取和维持的机制。我们进一步回顾了二价标记的存在如何影响基因组架构。最后，