http://www.ijdb.ehu.es/web/pdfdownload.php?doi=052049sn      (Full paper, PDF)

"Before programs: The physical origination of multicellular forms".

Stuart A. Newman ^1, *, Gabor Forgacs ², and Gerd B. Müller ³

¹ New York Medical College, Valhalla, NY, USA,
² University of Missouri, Columbia, MO, USA
³ University of Vienna, Wien, Austria

*Corresponding author e-mail: newman@nymc.edu

ABSTRACT:

By examining the formative role of physical processes in modern-day developmental systems, we infer that although such determinants are subject to constraints and rarely act in a "pure" fashion, they are identical to processes generic to all viscoelastic, chemically excitable media, non-living as well as living. The processes considered are free diffusion, immiscible liquid behavior, oscillation and multistability of chemical state, reaction-diffusion coupling and mechanochemical responsivity. We suggest that such processes had freer reign at early stages in the history of multicellular life, when less evolution had occurred of genetic mechanisms for stabilization and entrenchment of functionally successful morphologies. From this we devise a hypothetical scenario for pattern formation and morphogenesis in the earliest metazoa. We show that the expected morphologies that would arise during this relatively unconstrained "physical" stage of evolution correspond to the hollow, multilayered and segmented morphotypes seen in the gastrulation stage embryos of modern-day metazoa as well as in Ediacaran fossil deposits of ~600 Ma. We suggest several ways in which organisms that were originally formed by predominantly physical mechanisms could have evolved genetic mechanisms to perpetuate their morphologies.

Key words: self-organization, canalization, differential adhesion, epigenetic determinant, generative entrenchment

Links to RNA and Biological Causality:

Further Topics in:  Euchromatin,  active DNA, and  RNA  ribo-regulators:

Links to Euchromatin Activator RNA Reviews:
Links to Euchromatin Activator RNA Research:
Links to Ultrastructural Probes of DNase I-Sensitive Sites:
Links to RNA as a Therapeutic Agent:
Links to Hodgkin Lymphoma Immuno-Pathology:
Links to Activated T-Lymphocyte Immunotherapy:
Links to Medical Systems Biology:
Links to Selective Gene Transcription:
Links to RNA-Induced Epigenetics:
Links to RNA-Induced Embryogenesis:
Links to RNA and Biological Causality:
Links to Reprogramming and Neoplasia:

"Ultrastructural Probes of Active DNA Sites, and the RNA Activators of DNA".

For Further Information and Feedback:
E-mail: frenster@euchromatin.net