The evolution and conservation of left-right patterning mechanisms

M. Blum, K. Feistel, T. Thumberger, A. Schweickert
2014 Development  
Morphological asymmetry is a common feature of animal body plans, from shell coiling in snails to organ placement in humans. The signaling protein Nodal is key for determining this laterality. Many vertebrates, including humans, use cilia for breaking symmetry during embryonic development: rotating cilia produce a leftward flow of extracellular fluids that induces the asymmetric expression of Nodal. By contrast, Nodal asymmetry can be induced flow-independently in invertebrates. Here, we ask
more » ... n and why flow evolved. We propose that flow was present at the base of the deuterostomes and that it is required to maintain organ asymmetry in otherwise perfectly bilaterally symmetrical vertebrates.
doi:10.1242/dev.100560 pmid:24715452 fatcat:dx6wuxbtrjhf7kienafkuil364