Enter the variance in the allele frequency among different subpopulations and the variance of the allelic state in the total population into the Calculator. The calculator will evaluate the Fixation Index. 

Fixation Index Formula

FI = S/T

Variables:

  • FI is the Fixation Index ()
  • S is the variance in the frequency of the allele among different subpopulations.
  • T is the variance of the allelic state in the total population

To calculate Fixation Index, divide the variance in frequency of the allele among the subpopulations by the variance of the allelic state in the total population.

How to Calculate Fixation Index?

The following steps outline how to calculate the Fixation Index.

  • First, determine the variance in the frequency of the allele among different subpopulations. 
  • Next, determine the variance of the allelic state in the total population. 
  • Next, gather the formula from above = FI = S/T.
  • Finally, calculate the Fixation Index.
  • After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

variance in the frequency of the allele among different subpopulations = 0.34

variance of the allelic state in the total population = 0.89