Expected heterozygosity and Fst both quantify genetic variability. Explain the essential difference between these two quantities and for each give an example of one application.

2. Expected Heterozygosity (He)

formula

He​=1−∑pi²1

2. Expected Heterozygosity (He)

pi​ is

the frequency of the ith allele at the locus.

∑pi²1

sum of the squared allele frequencies.

Steps to Calculate Expected Heterozygosity:

1. do the steps for A first and then B

2. Square the frequency of each allele in the population.

3. Sum the squared frequencies for all alleles.

4. Subtract the sum of the squared frequencies from 1.

Calculate Fst between populations A and B. Show the steps in your calculations.

formula

Fst​=HT​​−HS​​/HT

Calculate Fst between populations A and B. Show the steps in your calculations.

• HT​:

total expected heterozygosity across both populations (the combined population).

Calculate Fst between populations A and B. Show the steps in your calculations.

• HSH_SHS​:

• Average expected heterozygosity within populations (mean of HeH_eHe​ for each population).

Calculate Fst between populations A and B. Show the steps in your calculations.

steps

1. average the 2 previous heterozygous values

2. Combined Allele Frequencies Formula of A and B = Pi

3. calculate HT

4. Calculate Fst

Combined Allele Frequencies Formula:

pi(T)​= (nA . Pi^(A))+ (nB . Pi^(B))/nA + nB

Combined Allele Frequencies Formula:

pi =

number on chart

pi(T)​=

combined frequency of a and b

the two numbers in the chart /2

Calculate Total Expected Heterozygosity (HT)

HT​=1−∑(pi(T)​)^2

1. square combined allele frequencies (piT)

2. sum squared frequencies

3. subtract from 1

Expected heterozygosity (He) quantifies

the probability of observing two different alleles at a given locus within a population.

expected heterozygosity (he)

It reflects

the genetic diversity within a population.

A high He value indicates

a high level of genetic variation within the population,

a low He value suggests lower

genetic diversity.

expected Heterozygosity (He​) What it measures

Genetic diversity within populations

expected Heterozygosity (He​) focus

Variability within a population

expected Heterozygosity (He​)

Application Example

Assessing genetic diversity in endangered species

Fst measures

Genetic differentiation between populations

Fst focus

Variability partitioned between populations

fst application example

studying population structure and migration