Xenbase Image ID: 145020

Fig. 7. Divergent modes of symmetry breakage in vertebrates. (A) Ancestral flow-based mode of chordates. The early gastrula organizer (node), which expresses Nodal (blue), differentiates into the notochord and somites during early neurulation. The notochord does not express Nodal and thus splits the Nodal-positive domain down the middle. Nodal-positive cells later integrate into the somites. (B) Divergent mechanism in chick and pig. The organizer (node) rotates during early gastrulation, which renders the node left-asymmetric. The notochord emerges over the right shoulder of the node and does not split the Nodal domain. Nodal thus becomes displaced to the left without the need for flow. Image published in: Blum M et al. (2014) Copyright © 2014. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View

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