• Open Access

Far from solved: A perspective on what we know about early mechanisms of left–right asymmetry

Authors

  • Laura N. Vandenberg,

    1. Biology Department, and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
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  • Michael Levin

    Corresponding author
    1. Biology Department, and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
    • Biology Department, and Tufts Center for Regenerative and Developmental Biology, Tufts University, Suite 4600, 200 Boston Avenue, Medford, MA 02155
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Abstract

Consistent laterality is a crucial aspect of embryonic development, physiology, and behavior. While strides have been made in understanding unilaterally expressed genes and the asymmetries of organogenesis, early mechanisms are still poorly understood. One popular model centers on the structure and function of motile cilia and subsequent chiral extracellular fluid flow during gastrulation. Alternative models focus on intracellular roles of the cytoskeleton in driving asymmetries of physiological signals or asymmetric chromatid segregation, at much earlier stages. All three models trace the origin of asymmetry back to the chirality of cytoskeletal organizing centers, but significant controversy exists about how this intracellular chirality is amplified onto cell fields. Analysis of specific predictions of each model and crucial recent data on new mutants suggest that ciliary function may not be a broadly conserved, initiating event in left–right patterning. Many questions about embryonic left–right asymmetry remain open, offering fascinating avenues for further research in cell, developmental, and evolutionary biology. Developmental Dynamics 239:3131–3146, 2010. © 2010 Wiley-Liss, Inc.

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