Sunday, February 09, 2014

Autogenesis: Life Before Genetics by Terrence Deacon


Terrence Deacon is the author of Incomplete Nature: How Mind Emerged from Matter (2013) and The Symbolic Species: The Co-evolution of Language and the Brain (1998). In the talk below, Deacon explores the "origins of life problem" by attempting to identify the necessary and sufficient molecular relationships required to transform inert chemicals into biological systems. Deacon introduces a model system - autogenesis - that redefines biological information and opens the search for life's origin to cosmic and planetary contexts seldom considered.
I begin with a simple molecular model system consisting of coupled reciprocal catalysis and self-assembly in which one of the catalytic bi-products tends to spontaneously self-assemble into a containing shell (analogous to a viral capsule). I term this dynamical relationship autogenesis because it is self-reconstituting in response to degradation. Self-reconstitution (and reproduction) is made possible by the fact that each of these linked self-organizing processes generates boundary constraints that promote and limit the other, and because this synergy thereby becomes embodied as a persistent rate-independent and substrate-indifferent higher order constraint on component constraint generation processes. It is proposed that this formal synergy is necessary and sufficient to constitute regulation as opposed to mere constraint. Two minor elaborations of this simple model system demonstrate that this simplest form of regulation can be the foundation for the evolution of two higher-order forms: cybernetic and template-based regulation.
You can read a PDF of a PowerPoint presentation at this link - the quote above is taken from the abstract to that presentation.

Life before genetics: autogenesis, and the outer solar system - Terrence Deacon (SETI Talks)

Streamed live on May 14, 2013


SETI Talks archive: http://seti.org/talks
 

The investigation of the origins of life has been hindered by what we think we know about current living organisms. This includes three assumptions about necessary conditions: 1) that it emerged entirely on Earth, 2) that it is dependent on the availability of liquid water, and 3) that it is coextensive with the emergence of molecules able to replicate themselves.

In addition, the three most widely explored alternative general models for a molecular process that could serve as a precursor to life also reflect reductionistically-envisioned fragments of current living systems: e.g. container-first, metabolism-first, or information-first scenarios. Finally, we are hindered by a technical concept of information that is fundamentally incomplete in precisely ways that are critical to characterizing living processes.

These all reflect reductionistic "top-down" approaches to the extent that they begin with a reverse-engineering view of what constitutes a living Earth-organism and explore possible re-compositional scenarios. This is a Frankensteinian enterprise that also begins with assumptions that are highly Earth-life specific and therefore unlikely to lead to a general exo-biology.

The approach Dr. Deacon will outline instead begins from an unstated conundrum about the origins of life. The initial transition to a life-like process necessarily exemplified two almost inconceivably incompatible properties: 1) it must have involved exceedingly simple molecular interactions, and 2) it must have embodied a thermodynamic organization with the unprecedented capacity to locally compensate for spontaneous thermodynamic degradation as well as to stabilize one or more intrinsically self-destroying self-organizing processes.

This talk will explore the origins of life problem by attempting to identify the necessary and sufficient molecular relationships able to embody these two properties. From this perspective Dr. Deacon will develop a model system - autogenesis - that redefines biological information and opens the search for life's origin to cosmic and planetary contexts seldom considered.
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