Strategies to establish left/right asymmetry in vertebrates and invertebrates

Curr Opin Genet Dev. 2007 Aug;17(4):351-8. doi: 10.1016/j.gde.2007.05.008. Epub 2007 Jul 23.


Left/right (L/R) asymmetry is essential during embryonic development for organ positioning, looping and handed morphogenesis. A major goal in the field is to understand how embryos initially determine their left and right hand sides, a process known as symmetry breaking. A number of recent studies on several vertebrate and invertebrate model organisms have provided a more complex view on how L/R asymmetry is established, revealing an apparent partition between deuterostomes and protostomes. In deuterostomes, nodal cilia represent a conserved symmetry-breaking process; nevertheless, growing evidence shows the existence of pre-cilia L/R asymmetries involving active ion flows. In protostomes like snails and Drosophila, symmetry breaking relies on different mechanisms, involving, in particular, the actin cytoskeleton and associated molecular motors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Actins / genetics
  • Actins / physiology
  • Animals
  • Body Patterning / genetics
  • Body Patterning / physiology*
  • Gene Expression Regulation, Developmental
  • Humans
  • Invertebrates / embryology*
  • Invertebrates / genetics
  • Models, Biological
  • Myosins / genetics
  • Myosins / physiology
  • Signal Transduction / genetics*
  • Signal Transduction / physiology
  • Vertebrates / embryology*
  • Vertebrates / genetics


  • Actins
  • Myosins