Evolution of DNA base composition under no-strand-bias conditions when the substitution rates are not constant
Open Access
- 1 January 1999
- journal article
- research article
- Published by Oxford University Press (OUP) in Molecular Biology and Evolution
- Vol. 16 (6) , 719-723
- https://doi.org/10.1093/oxfordjournals.molbev.a026156
Abstract
The evolution of DNA base composition evolution is simplified to a six-parameter model when there are no strand biases for mutation and selection. We analyzed the dynamics of this model with special attention to the influence of a change in substitution rates. The G + C content of the DNA sequence tends to an equilibrium value that is controlled by four parameters of the model. When the substitution rates are not constant, the G + C equilibrium position is not constant. The DNA sequence base frequencies always tend to a state in which A = T and G = C within a strand, regardless of substitution rates. This is true even when the substitution rates are not constant over time. This provides a simple way of rejecting the model from inspection of present-day DNA base composition.Keywords
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