Description
Return p(1-forward)+(1-p)backward and backward/(forward+backward).
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 p(1-forward)+(1-p)backward and backward/(forward+backward).
When to use this tool
Use Mutation Forward Backward Balance Term when you need a supplied one-step fitness or allele-frequency relationship.
How to use the tool and how it works
- Enter p, forwardRate, backwardRate. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read nextP, equilibriumP. Use the output convention below.
Require allele p and forward/backward mutation fractions in [0, 1] with positive rate sum. Return p(1-forward)+(1-p)backward and backward/(forward+backward).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| p | P | Required. Finite number; minimum 0; maximum 1. |
| forwardRate | Forward Rate | Required. Finite number; minimum 0; maximum 1. |
| backwardRate | Backward Rate | Required. Finite number; minimum 0; maximum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| nextP | Next P | Required. Finite number. |
| equilibriumP | Equilibrium P | Required. Finite number. |
{
"input": {
"p": 0.6,
"forwardRate": 0.01,
"backwardRate": 0.02
},
"output": {
"nextP": 0.602,
"equilibriumP": 0.6666666666666667
}
}Limitations and assumptions
- Forward removes the focal allele and backward adds it. This is a discrete per-generation mutation model, without selection, drift, migration or a continuous-time rate conversion.
- 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
- Migration Source Recipient Allele Gap
Form their weighted average and return migrantFraction×(source-recipient) as change.
- Selection One Generation Allele Update
Return that mean and [p²wAA+p(1-p)wAa]/mean as nextP.