Embryonic or induced stem cells replicate morphological steps and outcomes seen in intact embryos. This process is known as self-organization. This process has been discussed in the recent research paper by Stuart A. Newman in the research paper titled “Self-organization in embryonic development: myth and reality” that forms the basis of the following text.
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Importance of this research
The research provides instances of, and a conceptual framework for understanding, the relationships between transparently physical and evolved types of developmental self-organization. The difference between self-organizing development and not self-organizing development processes is illustrated.
About the research
In the words of the researchers,
The “self-organisation” term was introduced in the 18th century by the philosopher Immanuel Kant to describe the goal-directed properties of living systems, it came into modern use for non-living materials in which complex forms and patterns emerge through dynamical, energy-expending physical processes. What are the relationships among these uses of the term? While multicellular forms arose dozens of times from single-celled organisms, only some of these undergo development, and not all developmental processes are self-organizing. The evolution of the animals (metazoans) from unicellular holozoans was accompanied by the addition of novel gene products which mediated the constitution of the resulting cell clusters as liquid-, liquid crystal-, and solid-like materials with protean morphogenetic propensities. Such materials variously exhibited multilayering, lumen formation and elongation, echoing the self-organizing properties of nonliving matter, “generic” based on such parallels, though with biologically based subunit properties and modes of interaction. These effects provided evolutionary templates for embryonic forms and morphological motifs of diverse metazoan lineages. Embryos and organ primordia of present-day animal species continue to generate forms that resemble the outcomes of these physical effects. Their development, however, employs overdetermined, highly evolved mechanisms that are often disconnected from their originating processes. Using the examples of gastrulation, somitogenesis, and limb skeletal development, this chapter provides instances of, and a conceptual framework for understanding, the relationships between physical and evolved types of developmental self-organization.
Three examples from vertebrate embryogenesis are discussed in detail in the research paper. These examples of development are namely Gastrulation, Somitogenesis and Limb skeletogenesis. These development processes are demonstrated and classified with experimental evidence by the researchers.
- Gastrulation
Gastrulation is a formative process by which the three germ layers, which are precursors of all embryonic tissues, and the axial orientation are established in embryos in early animal development. Researchers have shared that for extant animals, any genuine physical self-organizing processes that may act during gastrulation are inextricably integrated into the complex developmental routines of these organisms, notwithstanding claims to have observed “self-organization” of gastrulation in vitro. - Somitogenesis
Somitogenesis is the process by which somites form. Somites are bilaterally paired blocks of paraxial mesoderm that form along the anterior-posterior axis of the developing embryo in segmented animals. In vertebrates, somites give rise to skeletal muscle, cartilage, tendons, endothelium, and dermis. It is classified as dynamical self-organization by the researchers because it mediates an emergent synchronized state. - Limb skeletogenesis: The jawed vertebrates (gnathostomes) typically have two sets of paired appendages, either fins or limbs. The process of Limb skeletogenesis was classified as a self-organization process by the researchers.
Conclusion
Animal embryos and developing organs are parcels of excitable soft matter. Thus, they will inevitably exhibit physical self-organizing effects. The researchers considered three processes – Gastrulation, Somitogenesis, and Limb skeletogenesis – to demonstrate the difference. The examples described in this chapter indicate that physical self-organization processes are employed in the embryos and organ primordia of extant animals. The studies differentiate between self-organization development and development in general.
Source: Stuart A. Newman’s Self-organization in embryonic development: myth and reality