Developmental Genetics, Department of Biomedicine, University of Basel Medical Faculty, Mattenstrasse 28, Basel, Switzerland.
Curr Opin Genet Dev. 2010 Aug;20(4):384-90. doi: 10.1016/j.gde.2010.04.014. Epub 2010 May 27.
Recent genetic and functional analysis of vertebrate limb development begins to reveal how the functions of particular genes and regulatory hierarchies can drastically change over time. The temporal and spatial interplay of the two instructive signalling centres are part of a larger signalling system that orchestrates limb bud morphogenesis in a rather self-regulatory manner. It appears that mesenchymal cells are specified early and subsequently, the progenitors for the different skeletal elements are expanded and determined progressively during outgrowth. Mutations and teratogens that disrupt distal progression of limb development most often cause death of the early-specified progenitors rather than altering their fates. The proliferative expansion and distal progression of paired appendage development was one of the main driving forces behind the transition from fin to limb buds during paired appendage evolution. Finally, the adaptive diversification or loss of modern tetrapod limbs in particular phyla or species appear to be a consequence of evolutionary tampering with the regulatory systems that control distal progression of limb development.
最近对脊椎动物肢体发育的遗传和功能分析开始揭示特定基因和调控层次的功能如何随时间发生巨大变化。两个有指导意义的信号中心的时空相互作用是一个更大的信号系统的一部分，该系统以相当自我调节的方式协调肢体芽形态发生。似乎间充质细胞很早就被指定，随后，不同骨骼元素的祖细胞在生长过程中逐渐扩大和确定。破坏肢体发育远端进展的突变和致畸物最常导致早期指定祖细胞的死亡，而不是改变它们的命运。成对附肢发育的增殖扩张和远端进展是从 fin 到肢体芽进化过程中从 fin 过渡到肢体芽的主要驱动力之一。最后，现代四足动物肢体的适应性多样化或丧失，特别是在特定的门或物种中，似乎是控制肢体发育远端进展的调节系统进化干扰的结果。
