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Substitution processes in molecular evolution. III. Deleterious alleles
1Section of Evolution and Ecology, University of California, Davis 95616.
Genetics
|November 1, 1994
Summary
This study examines deleterious allele evolution models. The house-of-cards model shows that substitutions are not exclusively deleterious, challenging prior claims and suggesting limitations for molecular evolution models.
Area of Science:
- Evolutionary biology
- Population genetics
- Molecular evolution
Background:
- Deleterious alleles play a crucial role in evolutionary processes.
- Understanding substitution rates is key to modeling molecular evolution.
- The house-of-cards model is a widely used framework for studying deleterious allele dynamics.
Purpose of the Study:
- To analyze substitution processes across different deleterious allele models.
- To evaluate the validity and applicability of the house-of-cards model.
- To identify suitable models for silent and protein evolution.
Main Methods:
- Computer simulations were employed to investigate allele substitution dynamics.
- Mathematical analyses were used to derive theoretical predictions.
- Various models were compared, including house-of-cards, exponential, gamma shift, Hartl-Dykhuizen-Dean (HDD), and optimum models.
Main Results:
- The substitution rate in the house-of-cards model is a concave function of selection strength (alpha).
- The house-of-cards model exhibits neutral behavior for alpha < 1 and stagnation for alpha > 4.
- Contrary to claims, the house-of-cards model involves both deleterious and advantageous substitutions.
- Only the optimum and HDD models are considered plausible for silent evolution.
Conclusions:
- The house-of-cards model is not a model of exclusively deleterious evolution.
- No biologically plausible models accurately represent exclusively deleterious substitutions in molecular evolution.
- Current models are inadequate for explaining protein evolution due to biological reasonableness and observed variability.
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