Introduction to provocative questions in left-right asymmetry.
Left-right asymmetry is a phenomenon that has a broad appeal-to anatomists, developmental biologists and evolutionary biologists-because it is a morphological feature of organisms that spans scales of size and levels of organization, from unicellular protists, to vertebrate organs, to social behaviour. Here, we highlight a number of important aspects of asymmetry that encompass several areas of biology-cell-level, physiological, genetic, anatomical and evolutionary components-and that are based on research conducted in diverse model systems, ranging from single cells to invertebrates to human developmental disorders. Together, the contributions in this issue reveal a heretofore-unsuspected variety in asymmetry mechanisms, including ancient chirality elements that could underlie a much more universal basis to asymmetry development, and provide much fodder for thought with far reaching implications in biomedical, developmental, evolutionary and synthetic biology. The new emerging theme of binary cell-fate choice, promoted by asymmetric cell division of a deterministic cell, has focused on investigating asymmetry mechanisms functioning at the single cell level. These include cytoskeleton and DNA chain asymmetry-mechanisms that are amplified and coordinated with those employed for the determination of the anterior-posterior and dorsal-ventral axes of the embryo.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
Biology Department, Allen Discovery Center at Tufts University, Medford, MA 02155, USA michael.levin@tufts.edu.
Michael
0000-0001-7292-8084
M
Levin
Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute, Center for Cancer Research, Frederick, MD 21702, USA klara@mail.nih.gov.
Amar J S
AJ
Klar
Department of Cell Biology and Anatomy, School of Medicine and Program in Women's and Gender Studies, College of Arts and Sciences, University of South Carolina, Columbia, SC 29208, USA ann.ramsdell@uscmed.sc.edu.
Ann F
AF
Ramsdell
D000818:Animals; D019521:Body Patterning; D047108:Embryonic Development; D056890:Eukaryota / Q000254:growth & development*; D010944:Plants / Q000196:embryology
DNA chirality; asymmetric cell division; developmental biology; developmental disorders; epigenetic mechanisms; human genetics