Computational Model of Artificial Life
SPONSORSHIP:
NASA
BRIEF DESCRIPTION
This research project involves studies of computational models for
aspects of
early life forms. We have investigated self-replication, an important
feature shared by many early life and pre-life forms, using cellular
automata
models. Using this model, a family of non-trivial self-replicating
structures
have been created which are substantially smaller and simpler than
those
created by previous methods, starting with Von Neumann's conjecture 40
uears
ago. An implication of this work is that self-replication ability does
not
have to be associated with life forms in a more advanced stage.
The current focus of this project is on the development of
computational
models for the formation of membranes and other forms of biological
compartment structures known as lipsomes from lipid-like polar
molecules
(amphiphiles). Lipsomes such as single layer micelles and reverse
micelles
and bilayer membranes have been conjectured to be crucial for the
evolution
of early life. It is not difficult to reproduce some of these
structures in
chemical experiments. However, without computational models, it is
difficult
to investigate at the molecular level the behavior of these structures
and the mechanism leading to their formation. Recently, we have
developed
one such model based on modeling inter-molecular forces stemmed from
the
basic physical and chemical properties of amphiphiles (e.g.,
hydrophobicity,
electro-statics, and gravity). The computer simulations of this model
demonstrated that simple structures such as micelles can be formed from
a pool of randomly distributed polar particles. Two possibilities will
be further explored toward the formation of bilayer
membranes. One is the formation of membranes from monolayers caused by
external perturbation or internal surface tension; and another from
collision
of several micelles. The resulting model will then be used to
investigate
important properties of membranes, include the effects of environmental
factors
(e.g., temperature, pH-value of the solvent, and the concentration of
lipids)
on the formation of different types of lipsomes; asymmetric permeation
of
chemicals through the walls of membranes; fission of large membranes to
form smaller ones, etc.
RELATED PAPERS
- Edwards
L., Peng, Y., and Reggia, J: “Computational Models for the
Formation of Protocell Structure”, Artificial
Life, 4(1), 61-77, 1998.
- Edwards,
L. and Peng, Y: “Computational Models for the Formation of Protocell Structures”, (a plenary talk presented
at the Sixth International Conference on Artificial Life), in Artificial
Life VI, Proceedings of The Sixth International Conference on
Artificial Life, Los Angeles, CA. June, 1998, 35-42.
- Reggia J, Armentrout S, Chou H, and Peng, Y: "Simple Systems
Exhibiting
Self-Directed Replication", Science, 259, 26
Feb. 1993, 1282-1287.
FOR MORE INFORMATION
Contact Yun Peng, ypeng@umbc.edu .