Portland State University. Department of Chemistry
Date of Award
Master of Science (M.S.) in Chemistry
1 online resource (vi, 51 pages)
RNA, Life -- Origin, Molecular evolution
We describe the initial realization of behavior in the biosphere, which we term behavioral chemistry. If molecules are complex enough to attain a stochastic element to their structural conformation in such a way as to radically affect their function in a biological (evolvable) setting, then they have the capacity to behave. This circumstance is described here as behavioral chemistry, unique in its definition from the colloquial chemical behavior. This transition between chemical behavior and behavioral chemistry need be explicit when discussing the root cause of behavior, which itself lies squarely at the origins of life and is the foundation of choice. RNA polymers of sufficient length meet the criteria for behavioral chemistry and therefore are capable of making a choice.
We test these theoretical findings with a empirical systems; since RNA simultaneously possesses evolvability and catalytic function we set to construct a model system. Firstly, during in vitro transcription of the Chlorella PBCV-1 pdg intron, we observed multiple RNAs of slower electrophoretic mobility along with the expected 98-nucleotide
transcript. The preferences observed for TI or linear RNA for the pdg intron are manifestations of alternative phenotypic states and represent evidence of behavior at the chemical level. Secondly, we provide a basis for the marriage between empirical findings and the philosophical studies of biosemiotics. As well, provide a basis for the minimal criteria for an interpretative response and suggest that interpretation is evolvable. The studies hold relevance to the origins of life showing a minimal system capable of carrying out a choice based on the environment. We have shown this phenomenon is not an intrinsic characteristic to all RNAs and that the Tetrahymena ribozyme recognizes the presence of the object through the sensing of a sign.
Larson, Brian, "Interpretation of Chemical Environments by RNA and the Implications to the Origins of Life" (2014). Dissertations and Theses. Paper 1705.