Müller G
Bibl Anat. 1986(29):91-108.
The skeletal influence on muscle development was investigated taking an experimental and comparative approach. Chick hindlimbs of HH stage 23 were operated in order to induce the development of an enlarged, elongated fibula - similar to the condition in bird ancestors. The skeletal change resulted in a series of secondary alterations in the later-forming zeugopod muscles. By comparing the results to the zeugopod musculature in other birds and in reptiles it could be shown that changes did not occur at random but resembled the patterns of interspecific variation and ancestral arrangement. It is concluded that skeletal elements influence muscle morphogenesis during a certain period of development. A classification of four phases in muscle development is presented: formation of the premuscular masses; individuation of separate muscles; final shaping and insertion; development maintenance and growth. The factors acting on each level are discussed and it is suggested that skeletal influence becomes effective in phase 3. The results also emphasize the role of development in evolution. The experimental reestablishment of an ancestral epigenetic condition within a developing organ system resulted in ancestral features of subsequently forming characters. This suggests that modification of epigenetic control of gene expression may be an important mechanism in evolutionary change.
采用实验和比较的方法研究了骨骼对肌肉发育的影响。对处于HH第23阶段的鸡后肢进行手术，以诱导发育出增大、延长的腓骨，类似于鸟类祖先的情况。骨骼变化导致了后期形成的zeugopod肌肉发生一系列继发性改变。通过将结果与其他鸟类和爬行动物的zeugopod肌肉组织进行比较，可以发现变化并非随机发生，而是类似于种间变异和祖先排列的模式。得出的结论是，骨骼元素在发育的特定时期影响肌肉形态发生。提出了肌肉发育的四个阶段分类：肌肉前体的形成；单个肌肉个体化；最终塑形和附着；发育维持和生长。讨论了作用于每个阶段的因素，并认为骨骼影响在第3阶段变得有效。结果还强调了发育在进化中的作用。在发育中的器官系统内实验性地重建祖先的表观遗传条件导致了随后形成特征的祖先特征。这表明基因表达的表观遗传控制的改变可能是进化变化中的一个重要机制。
