Life systems, in general, consist of diverse components and maintain themselves and can reproduce themselves. It is hierarchical in nature, as molecule, cell, organism, and ecosystem, whereas it is marvelous that such hierarchical system with diverse components at each level（e.g., molecule species, cell types, species）achieves robustness to perturbations and sustains and reproduces itself. Here, we adopt consistency between different hierarchical levels as a guiding principle to understand such system: In spite of huge differences in spatiotemporal scales, the changes in each level are highly correlated. Following this macro-micro consistency principle, we aim to formulate general laws and uncover universal properties in adaptation in cellular systems, development with differentiation, constraint and direction in phenotypic evolution, and resilient ecosystems. The topics include origin of reproducing cells from a collective of chemical reactions, constraints and direction in phenotypic evolution, evolutionary fluctuation-response relationship, generic mechanism for adaptation, dynamics for irreversible differentiation and reprogramming, conditions for diversification in ecological social systems.
Theoretical Foundation of Universal Biology: By bridging between physics and biology, we aim to establish theoretical formulation and uncover fundamental concepts for complex, hierarchical bio-systems, and provide common tools to uncover general laws in reproduction, adaptation, evolution, and diversification therein.
- General formulation for systems sustaining multi-level consistency, to unveil general laws therein
- Origin of protocells that reproduce diverse components with transferring genetic information
- Adaptation to, and memory of, unforeseen environmental challenges
- Evolutionary dimensional reduction from high-dimensional dynamical systems
- Reciprocity between robustness (unchangeability) and plasticity (changeability)
Universal Constraint and Direction in Evolution and Development: Noting consistency and robustness among processes of distinct spatiotemporal time-scales in development and evolution, we aim to extract general constraints and characteristics therein, focusing on robustness in developmental and evolutionary process (homeorhesis).
- Direction and constraints in phenotypic evolution, and prediction and control of evolution
- Origin of multicellular organisms in terms of multi-level evolution
- Evolution-development congruence
- Dynamical-systems theory for reprogramming, i.e., operation to reverse irreversible cell differentiation
- Cancer as a collapse of cell-organism consistency
Dynamics, sustainability and evolution of eco-systems: We aim at understanding how an ecosystem with diversity evolves and achieves resilience against perturbations. What perturbation will destroy the ecosystem to lose the diversity, and how can one control the ecosystem to regain diversity? We answer these questions by noting the consistency principle between macroscopic (ecosystem) and microscopic levels (species or individuals), by referring also to experiments of microbial ecosystem and artificial biosphere.
- Condition for resilient ecosystem, evolution and sustainability of diverse ecosystem
- Evolution of plasticity and robustness in ecosystem
Dynamic Cognition and Neural Information Processing: By focusing on consistency between collective dynamics of neural activities and slow learning process, we formulate a theory for biological cognitive process, which will provide an approach, complementary to the current machine learning.
- Direction and constraint in learning (akin to the evolution theory above)
- Relevance of chaotic spontaneous neural activity to flexible cognition process
- Context-dependent information processing
Universal Anthropology and Sociology: Of course, human society is a striking example of a robust, hierarchical system, in which the concept of micro-macro consistency and multi-level evolution can be applied. Classification of possible robust societies and the direction and constraints in the historical evolution will also give a key to understand how stable development of our future society is possible.
- Direction and constraints in patterns and evolution of human societies
- Robustness in socio-economic systems
- Chance and necessity in human history
Primary fields of research
Theoreical Biophysics, Complex Systems, Chaos, Nonlinear Dynamics, Unviersal Biology