Vertebrates exhibit striking left–right (L–R) asymmetries in the structure and position of the internal organs. Symmetry is broken by motile cilia-generated asymmetric fluid flow, resulting in a signaling cascade – the Nodal–Pitx2 pathway – being robustly established within mesodermal tissue on the left side only. This pathway impinges upon various organ primordia to instruct their side-specific development. Recently, progress has been made in understanding both the breaking of embryonic L–R symmetry and how the Nodal–Pitx2 pathway controls lateralized cell differentiation, migration, and other aspects of cell behavior, as well as tissue-level mechanisms, that drive asymmetries in organ formation. Proper execution of asymmetric organogenesis is critical to health, making furthering our understanding of L–R development an important concern.

脊椎动物在内部器官的结构和位置上表现出明显的左右不对称。运动性纤毛产生的不对称流体流动破坏了对称性，从而仅在左侧的中胚层组织内牢固建立了信号级联-Nodal–Pitx2途径。该途径影响各种器官原基，以指示它们的侧特异性发育。最近，在了解打破胚胎L–R对称性以及Nodal–Pitx2途径如何控制细胞的侧化细胞分化，迁移和细胞行为的其他方面，以及在组织水平上驱动非对称性的机制方面，已经取得了进展。器官形成。正确执行不对称器官发生对健康至关重要，这使我们对L–R发育的了解成为一个重要问题。