Čtvrtá vrstva

Germ-layers, neural crest cells and the vertebrate evolution from the evo-devo view-point by Robert Černý.

In this text it is claimed that neural crest cells, a population of highly migrated embryonic cells that are specific to vertebrates, represent in fact an embryonic source for the majority of sharedderived features of vertebrates. Consequently, after discussing some topics of the germ-layer theory, it is argued that neural crest cells might be understand as the forth germ-layer of vertebrates (after the ecto-, ento-, and mesoderm) and vertebrates can be seen as tetrablastic, not triploblastic animals.