Showing papers by "Stuart A. Newman published in 2012"

Physico-Genetic Determinants in the Evolution of Development

Abstract: Animal bodies and the embryos that generate them exhibit an assortment of stereotypic morphological motifs that first appeared more than half a billion years ago. During development, cells arrange themselves into tissues with interior cavities and multiple layers with immiscible boundaries, containing patterned arrangements of cell types. These tissues go on to elongate, fold, segment, and form appendages. Their motifs are similar to the outcomes of physical processes generic to condensed, chemically excitable, viscoelastic materials, although the embryonic mechanisms that generate them are typically much more complex. I propose that the origins of animal development lay in the mobilization of physical organizational effects that resulted when certain gene products of single-celled ancestors came to operate on the spatial scale of multicellular aggregates.

Dynamical patterning modules in plant development and evolution

Abstract: Broad comparative studies at the level of developmental processes are necessary to fully understand the evolution of development and phenotypes. The concept of dynamical patterning modules (DPMs) provides a framework for studying developmental processes in the context of wide comparative analyses. DPMs are defined as sets of ancient, conserved gene products and molecular networks, in conjunction with the physical morphogenetic and patterning processes they mobilize in the context of multicellularity. The theoretical framework based on DPMs originally postulated that each module generates a key morphological motif of the basic animal body plans and organ forms. Here, we use a previous definition of the plant multicellular body plan and describe the basic DPMs underlying the main features of plant development. For each DPM, we identify characteristic molecules and molecular networks, and when possible, the physical processes they mobilize. We then briefly review the phyletic distribution of these molecules across the various plant lineages. Although many of the basic plant DPMs are significantly different from those of animals, the framework established by a DPM perspective on plant development is essential for comparative analyses aiming to provide a truly mechanistic explanation for organic development across all plant and animal lineages.

Synthetic Biology: Life as App Store

Abstract: Since the early 19 century, scientists have proposed a variety of naturalistic explanations for the organization of matter in living systems, particularly its origin and propagation from parent to offspring. Some biologists (selectionists; adaptationists) favor the idea that such organization arises by natural selection exerted on living materials with little intrinsic structure of their own. Others (structuralists; physicalists) say the complex materials that living creatures are made of have inherent self-organizational properties that determine what the life forms are and how they develop. The lack of conclusive answers despite decades of research and tens of thousands of published studies has allowed empirically unfounded creationist beliefs to persist in broad sectors of the population (Newman 2008). The still primitive understanding of the material basis of living systems also continues to instill awe in scientists, most of whom probably consider the notion of rationally designing organisms an impractical dream. However, the new field of synthetic biology now aims to change this. As I describe below, with its modus operandi of sidestepping biological origins and complexity in favor of simplification and application, ironically*and despite the intentions of the majority of scientists involved*the synthetic biology enterprise verges uncomfortably close to the metaphysics of creationism.