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Biomedical subjects

I Karafyllidis

Publications and source records attributed to I Karafyllidis.

3 recordsLinked to original sources

An algorithm for the study of DNA sequence evolution based on the genetic code.

Recent studies of the quantum-mechanical processes in the DNA molecule have seriously challenged the principle that mutations occur randomly. The proton tunneling mechanism causes tautomeric transitions in base pairs resulting in mutations during DNA replication. The meticulous study of the quantum-mechanical phenomena in DNA may reveal that the process of mutagenesis is not completely random. We are still far away from a complete quantum-mechanical model of DNA sequence mutagenesis because of the complexity of the processes and the complex three-dimensional structure of the molecule. In this paper we have developed a quantum-mechanical description of DNA evolution and, following its outline, we have constructed a classical model for DNA evolution assuming that some aspects of the quantum-mechanical processes have influenced the determination of the genetic code. Conversely, our model assumes that the genetic code provides information about the quantum-mechanical mechanisms of mutagenesis, as the current code is the product of an evolutionary process that tries to minimize the spurious consequences of mutagenesis. Based on this model we develop an algorithm that can be used to study the accumulation of mutations in a DNA sequence. The algorithm has a user-friendly interface and the user can change key parameters in order to study relevant hypotheses.

Algorithms↗

A cellular automaton model for the study of DNA sequence evolution.

Cellular automata are introduced as a model for DNA structure, function and evolution. DNA is modeled as a one-dimensional cellular automaton with four states per cell. These states are the four DNA bases A, C, T and G. The four states are represented by numbers of the quaternary number system. Linear evolution rules, represented by square matrices, are considered. Based on this model a simulator of DNA evolution is developed and simulation results are presented. This simulator has a user-friendly input interface and can be used for the study of DNA evolution.

Evolution, Molecular↗

A model for the influence of the greenhouse effect on insect and microorganism geographical distribution and population dynamics.

A model for the influence of the greenhouse effect on insect and microorganism geographical distribution and population dynamics using cellular automata is presented. Based on this model, an algorithm has been developed and used to determine the geographical distribution and population dynamics of a hypothetical species in an scenario of global warming. The species' initial population distribution is assumed to be Gaussian. After the initiation of global warming, the population moves and after a few decades the population distribution is no longer Gaussian. Larger populations are found in the direction of population movement.

Algorithms↗