Description
Return rate 1/(2N), mean time 2N and survival exp(-elapsed/(2N)).
Population-genetic probabilities depend on copy counts, ploidy, effective size and model assumptions. A neutral fixation identity and a selected diffusion approximation describe different conditions; neither guarantees an actual evolutionary outcome.
Return rate 1/(2N), mean time 2N and survival exp(-elapsed/(2N)).
When to use this tool
Use Coalescent Two Lineage Rate Term when you need the stated population-count, coalescent or fixation-model term.
How to use the tool and how it works
- Enter effectiveDiploids, elapsedGenerations. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read rate, meanTime, survival. Use the output convention below.
Require positive effectiveDiploids and nonnegative elapsed generations. Return rate 1/(2N), mean time 2N and survival exp(-elapsed/(2N)).1
The diploid coalescent scale gives a constant-population pairwise waiting-time mean of 2Ne generations. This tool evaluates its continuous exponential model without simulating ancestry.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| effectiveDiploids | Positive effective number of diploid individuals, not gene copies. | Required. Finite number; strictly above 0. |
| elapsedGenerations | Elapsed Generations | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| rate | Supplied rate on the period and denominator basis stated above. | Required. Finite number. |
| meanTime | Mean exponential coalescent waiting time in generations. | Required. Finite number. |
| survival | Survival | Required. Finite number. |
{
"input": {
"effectiveDiploids": 100,
"elapsedGenerations": 200
},
"output": {
"rate": 0.005,
"meanTime": 200,
"survival": 0.36787944117144233
}
}Limitations and assumptions
- This is the continuous exponential two-lineage diploid coalescent approximation, not an exact finite-generation geometric waiting distribution or a full genealogy simulation.
- 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 the appropriate population-genetic analysis and data to estimate effective size, selection and uncertainty. Keep actual census counts, effective population conventions and discrete versus continuous-time approximations distinct.
References
Similar or alternative tools
- Fixation Probability Neutral Copy Term
Return copy frequency as neutral fixationProbability.
- Adaptation Fixation Supplied Effect Term
Return p at x zero, otherwise the diffusion ratio (1-exp(-xp))/(1-exp(-x)), using stable sign-specific exponential forms.