LABORATORY OF THEORETICAL BIOLOGY AND COMPLEXITY

Office: Los Alerces 3024, Ñuñoa, Santiago, Chile

Fone: (56-2) 2384101

Director of Institute of Philosophy and Complexity Sciences

Research

The central area of interest of the lab is the interdisciplinary use of theoretical tools from mathematics and informatics to model biological and other kinds of complex systems. Specifically, projects focus on developing theory of multidimensional phase spaces to model evolutionary, ecological, neurobiological and social processes. The lab is also characterized by the discussion on conceptual and philosophical issues involved in theoretical modeling and complexity.

On-going research interests

Modeling evolution in multidimensional phase spaces

The Fisher geometrical model represents evolution as a walk in a phase space of phenotypic quantitative traits (axes) in which the origin corresponds to a local optimum for the combination of traits (see Figure below). Complexity is represented by the number of dimensions.

We study molecular and phenotypic evolution in the multidimensional Fisher's geometrical model. We emphasize the power of simulational results in the quest for obtaining more realistic results of evolutionary processes.

Publications:

P. RAZETO-BARRY, J. DÍAZ, D. COTORAS & R. A. VÁSQUEZ. 2011. Molecular evolution, mutation size and gene pleiotropy: a geometric reexamination. Genetics 187(3): 877-885.

P. RAZETO-BARRY & K. MALDONADO. 2011. Adaptive contributions of cis-regulatory regions may involve a small number of mutations. Evolution 64(11): 3332-3335.

P. RAZETO-BARRY, J. DÍAZ & R. A. VÁSQUEZ. 2011. The nearly-neutral and selection theories of molecular evolution in the Fisher geometrical framework: substitution rate, population size and complexity. Genetics 191(2) (in press).

Randomness in complex systems

Randomness in neurobiology: Waves can be represented as rotating vectors in the bidimensional complex space (phasors). The superposition of waves can be represented as the vectorial summation of such phasors. If the superposition of neurobiological waves is perfectly asynchronous, the process can be represented as a bidimensional random walk. We focus on developing theory and statistical methods for analyzing neurobiological waves in bidimensional phase spaces.

Publications:

J. DÍAZ, P. RAZETO-BARRY, J.C. LETELIER, J. CAPRIO, J. BACIGALUPO. 2007. Amplitude modulation patterns of local field potentials reveal asynchronous neuronal populations. The Journal of Neuroscience 27(34):9238-9245.

This paper in the cover illustration of the journal's issue:

In coolaboration with: Javier Díaz.

Multidimensional random walks: mathematics, evolution and physics: The multidimensional random walk represents the simplest null model for processes that are represented as walks in a multidimensional space. Although the random walk problem was proposed 105 years ago, solutions are very intrincate. We found symple ways to solve the d-dimensional random walk problem. We apply previous results to model neutral, pan-neutral and nearly neutral evolution at the phenotypic level. Also we found the multidimensional Maxwell-Boltzmann distribution.

Publications:

P. RAZETO-BARRY & J. DÍAZ. 2011. A very simple solution of the multidimensional random walk problem. (In review)

P. RAZETO-BARRY & J. DÍAZ. 2012. Multidimensional random walks species and gases. (submitted).

P. RAZETO-BARRY 2012. Evolutionary random flights, or on the tendency of varieties to depart indefinitely from the original type. (in elaboration)

Cellular automata and ecology

Ecological and environmental questions have a promising way to be analyzed by cellular automata. In the lab we study social and ecological factors that impact the environment via the cellular automata modeling. This tool enable us deepen into theoretical and predictive questions about the impact of humans and native species on ecosystems.

Publications:

R. DELGADO. 2010. ¿Cómo la expansión de los asentamientos humanos afecta la biodiversidad? Un estudio de la importancia de las condiciones históricas iniciales mediante un modelo basado en agente. MSc. Thesis, Universidad Bolivariana-IFICC. (Advisor: P. RAZETO-BARRY)

P. GONZÁLEZ-GÓMEZ, N. RICOTE-MARTINEZ, P. RAZETO-BARRY, IVANIA S. COTORÁS & F. BOZINOVIC. 2010. Thermoregulatory cost affects territorial behavior in hummingbirds: a model and its application. Behavioral Ecology and Sociobiology 65:2141–2148.

K. MALDONADO, P. RAZETO-BARRY & P. SABAT 2011. Individual specialization and phenotypic flexibility: a cellular automata model and its examination using passerine bird populations. (In elaboration)

M. MOLINA-MONTENEGRO, P. RAZETO-BARRY et al. 2011. Plant invasions in the Antarctic continent: vectors and consequences (In elaboration)

Philosophical and social modeling interests

Conceptual analysis in philosophy of science and social modeling are two related interests of the lab. Philosophical issues about probabilistic causation are important to develop more interpretable and feasible models. We discuss philosophical problems related to natural selection, origin of life and social evolution. Also we develop social models to represent cultural and social evolutionary processes via artificial chemistry and multiagent modeling.

Publications:

P. RAZETO-BARRY & R. FRICK. 2011. Probabilistic causation and the explanatory role of natural selection. Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 42(3):344-355.

P. RAZETO-BARRY & J. CIENFUEGOS. 2011. La paradoja de la probabilidad de lo improbable y el pensamiento evolutivo de Niklas Luhmann. Convergencia 57:13-38. (ISI)

T. VELOZ, P. RAZETO-BARRY, P. DITTRICH & A. FAJARDO. 2011. Chemical organizations and game theory.Journal of Mathematical Biology (in resubmission)

P. RAZETO-BARRY. 2011. ¿Qué es autopoiesis? Quarterly Review of Biology (In review)

C. BLANCO. 2011. Presiones de selección comunicativa: Una modelación basada en agentes para la explicación de patrones globales de diversidad cultural. MSc. Thesis Magister en Análisis Sistémico Aplicado a la Sociedad, Facultad de Ciencias Sociales, Universidad de Chile. (Advisor: P. RAZETO-BARRY)

RAZETO-BARRY, P. 2012. Una adaptación interpretada del Poema de Parménides. Acta Literaria (En revisión).