Koop Demian, Holland Linda Z
Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0202, USA.
Birth Defects Res C Embryo Today. 2008 Sep;84(3):175-87. doi: 10.1002/bdrc.20128.
This review examines the basal chordate, amphioxus, as a simple model for providing insights into the development and evolution of the vertebrates, with which it shares many features, including a pharynx perforated with gill slits, a dorsal nerve cord, segmented muscles, and a notochord. Conversely, amphioxus is simpler than vertebrates in lacking neural crest and paired cephalic sensory organs. Amphioxus embryos are less derived than those of vertebrates, because it lacks large quantities of yolk and/or extra-embryonic tissues. Embryogenesis involves only a simple folding of tissue layers. In addition, the amphioxus genome lacks the large-scale gene duplications of vertebrates. However, in spite of the comparative simplicity of amphioxus, its developmental mechanisms are proving to be highly conserved with those of vertebrates. Thus, studies of amphioxus development can shed light on similar, but more complex, development of vertebrates. Such studies are especially interesting for their insights into the genetic basis of craniofacial birth defects in humans.
本综述将文昌鱼这种基部脊索动物作为一个简单模型，以深入了解脊椎动物的发育和进化，文昌鱼与脊椎动物有许多共同特征，包括有鳃裂穿孔的咽、背神经索、分节的肌肉和脊索。相反，文昌鱼比脊椎动物简单，因为它缺乏神经嵴和成对的头部感觉器官。文昌鱼胚胎比脊椎动物胚胎的分化程度低，因为它缺乏大量卵黄和/或胚外组织。胚胎发生仅涉及组织层的简单折叠。此外，文昌鱼基因组缺乏脊椎动物那样的大规模基因复制。然而，尽管文昌鱼相对简单，但其发育机制已被证明与脊椎动物高度保守。因此，对文昌鱼发育的研究可以揭示脊椎动物类似但更复杂的发育情况。这类研究对于深入了解人类颅面出生缺陷的遗传基础尤其有趣。
