Simulation and Analysis of an Evolutionary Model of Deoxyribonucleic Acid (DNA).

摘要

A Monte Carlo simulation model was developed in order to evaluate model predictions with expectations of the evolutionary hypothesis of nearly neutral point mutations. The beta chain of hemoglobin was chosen as the strand of deoxyribonucleic acid (DNA) to be analyzed due to the extensive characterization of point mutations along the 146 amino acids of the protein chain. The nucleotide sequences of human, rabbit and a hypothetical ancestral hemoglobin were used as a starting point in the simulation. Three models of point mutations were tested. Equiprobable mutation from one nucleotide to any of the remaining three nucleotides composing DNA was one model. The second model incorporated observed first order probability of transition from each nucleotide to the remaining three nucleotides composing DNA using observed probabilities from three independent assessments. The third model was an Ising type model employing a probability of nucleotide change based on the nucleotide composition of the nearest neighbors. Use of these models resulted in evidence to suggest that five methods of simulating the mutations in an evolutionary system produced results that primarily differed in the way in which nulceotide changes resulted in a pattern of amino acid changes.