Description
Return relative fitness and one minus that ratio as selectionCoefficient.
Population-genetic fitness models use explicit allele frequencies, genotype fitnesses and generation rules. Relative fitness and a selection coefficient require a sign convention, and a deterministic update describes a model rather than an observed population trajectory.
Return relative fitness and one minus that ratio as selectionCoefficient.
When to use this tool
Use Selection Reference Fitness Sign when you need a supplied one-step fitness or allele-frequency relationship.
How to use the tool and how it works
- Enter fitness, referenceFitness. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read relativeFitness, selectionCoefficient. Use the output convention below.
Require nonnegative fitness and positive reference fitness. Return relative fitness and one minus that ratio as selectionCoefficient.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| fitness | Fitness | Required. Finite number; minimum 0. |
| referenceFitness | Reference Fitness | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| relativeFitness | Relative Fitness | Required. Finite number. |
| selectionCoefficient | 1-relativeFitness; negative when focal fitness exceeds reference. | Required. Finite number. |
{
"input": {
"fitness": 0.8,
"referenceFitness": 1
},
"output": {
"relativeFitness": 0.8,
"selectionCoefficient": 0.19999999999999996
}
}Limitations and assumptions
- The convention makes advantageous relative fitness yield negative selectionCoefficient. It does not estimate fitness, infer causation or determine reproductive outcomes.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use a population model appropriate to mating, selection, mutation, migration and drift. Estimate parameters and uncertainty from suitable data instead of treating a supplied model step as a prediction.
References
Similar or alternative tools
- Selection Dominance Coefficient Fitness Gap
Return fitnesses 1, 1-hs and 1-s.
- Selection One Generation Allele Update
Return that mean and [p²wAA+p(1-p)wAa]/mean as nextP.