Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, 92093-0349, USA.
Nat Rev Genet. 2008 Sep;9(9):663-77. doi: 10.1038/nrg2417.
The genetic systems controlling body axis formation trace back as far as the ancestor of diploblasts (corals, hydra, and jellyfish) and triploblasts (bilaterians). Comparative molecular studies, often referred to as evo-devo, provide powerful tools for elucidating the origins of mechanisms for establishing the dorsal-ventral and anterior-posterior axes in bilaterians and reveal differences in the evolutionary pressures acting upon tissue patterning. In this Review, we focus on the origins of nervous system patterning and discuss recent comparative genetic studies; these indicate the existence of an ancient molecular mechanism underlying nervous system organization that was probably already present in the bilaterian ancestor.
控制体轴形成的遗传系统可以追溯到二胚层动物（珊瑚、水螅和水母）和三胚层动物（两侧对称动物）的祖先。比较分子研究，通常被称为进化发育生物学，为阐明在两侧对称动物中建立背-腹和前-后轴的机制的起源提供了强大的工具，并揭示了作用于组织模式形成的进化压力的差异。在这篇综述中，我们重点讨论神经系统模式形成的起源，并讨论最近的比较遗传研究；这些研究表明，存在一种古老的分子机制，可能已经存在于两侧对称动物的祖先中。
