Evolutionary developmental biology and vertebrate head segmentation: A perspective from developmental constraint

摘要: The question of vertebrate head segmentation has become one the central issues in Evolutionary Developmental Biology. Beginning as a theory based comparative anatomy, segmental been adopted and further developed by embryologists. With use molecular cellular biology, particular analyses Hox gene complex, addressed at new levels, but it remains unresolved. In this review, is reevaluated, introducing findings from experimental embryology evolutionary biology. biology shown that pattern generated through hierarchically organized causally linked series events. can be viewed generative constraint, whether imposed underlying patterns, trunk. respect, amphioxus appears to segmented along entire anteroposterior axis, with myotomes peripheral nerves repeating same rhythm (somitomerism). Similarly, trunk, patterns shared myotomes, vertebrae are derived somites. However, vertebrates there no such mesodermal pattern, although neuromerism branchiomerism do indicate presence constraints rhombomeres pharyngeal pouches, respectively. These data fit better concept dual metamerism body proposed Romer (1972), than traditional cavity-based model Goodrich (1930).