Title
Modeling genome evolution with a diffusion approximation of a birth-and-death process
Abstract
Motivation: In our previous studies, we developed discrete-space birth, death and innovation models (BDIMs) of genome evolution. These models explain the origin of the characteristic Pareto distribution of paralogous gene family sizes in genomes, and model parameters that provide for the evolution of these distributions within a realistic time frame have been identified. However, extracting the temporal dynamics of genome evolution from discrete-space BDIM was not technically feasible. We were interested in obtaining dynamic portraits of the genome evolution process by developing a diffusion approximation of BDIM. Results: The diffusion version of BDIM belongs to a class of continuous-state models whose dynamics is described by the Fokker--Plank equation and the stationary solution could be any specified Pareto function. The diffusion models have time-dependent solutions of a special kind, namely, generalized self-similar solutions, which describe the transition from one stationary distribution of the system to another; this provides for the possibility of examining the temporal dynamics of genome evolution. Analysis of the generalized self-similar solutions of the diffusion BDIM reveals a biphasic curve of genome growth in which the initial, relatively short, self-accelerating phase is followed by a prolonged phase of slow deceleration. This evolutionary dynamics was observed both when genome growth started from zero and proceeded via innovation (a potential model of primordial evolution), and when evolution proceeded from one stationary state to another. In biological terms, this regime of evolution can be tentatively interpreted as a punctuated-equilibrium-like phenomenon whereby evolutionary transitions are accompanied by rapid gene amplification and innovation, followed by slow relaxation to a new stationary state. Contact: koonin@ncbi.nlm.nih.gov
Year
DOI
Venue
2005
10.1093/bioinformatics/bti1202
Bioinformatics
Keywords
Field
DocType
pareto distribution,diffusion model,stationary distribution,diffusion approximation,gene amplification,gene family,stationary state,punctuated equilibrium,genome evolution
Genome,Pareto distribution,Computer science,Genome evolution,Stationary distribution,Bioinformatics,Evolutionary dynamics,Stationary state,Pareto principle,Heavy traffic approximation
Journal
Volume
Issue
ISSN
21
3
1367-4803
Citations 
PageRank 
References 
4
0.56
4
Authors
3
Name
Order
Citations
PageRank
Georgy P. Karev1244.08
Faina S. Berezovskaya272.04
Eugene V. Koonin3986239.69