title: Physics of amniote formation.
abstract: We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally.
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot/CNRS, 10 rue Alice Domont et Léonie Duquet, Paris 75013, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Fleury
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot/CNRS, 10 rue Alice Domont et Léonie Duquet, Paris 75013, France.
authors.forename: Ameya Vaishnavi
authors.initials: AV
authors.lastname: Murukutla
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot/CNRS, 10 rue Alice Domont et Léonie Duquet, Paris 75013, France.
authors.forename: Nicolas R
authors.initials: NR
authors.lastname: Chevalier
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot/CNRS, 10 rue Alice Domont et Léonie Duquet, Paris 75013, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gallois
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot/CNRS, 10 rue Alice Domont et Léonie Duquet, Paris 75013, France.
authors.forename: Marina
authors.initials: M
authors.lastname: Capellazzi-Resta
authors.affiliation: Alligator Bay, 62 route du Mont Saint-Michel, Beauvoir 50170, Manche, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Picquet
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot/CNRS, 10 rue Alice Domont et Léonie Duquet, Paris 75013, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Peaucelle
mesh_terms: D000489:Alligators and Crocodiles / Q000196:embryology; D000650:Amnion / Q000196:embryology*; D000818:Animals; D055592:Biophysical Phenomena; D001717:Birds / Q000196:embryology; D004625:Embryo, Nonmammalian