1. Chapter 4 Population Genetics
Chapter 4 Population Genetics
Diversity Within Versus Diversity Among Populations

2. Orchis
O. isozymus O. polyzymus

3. O. isozymus O. polyzymus

4. Your Goal apply population genetics concepts to conservation planning
specifically, if you have funding to save only four wetlands, which ones will it be?

5. Review this demonstration!

9. Determine allele frequencies
Determine frequencies of “fast” and “slow”.
tally the number of alleles among the 15 individuals
divide it by the total number of alleles present in the population.

11. Determine Allele Frequencies for Slow and Fast
add the number of alleles across all 15 individuals; divide by the total # of alleles
remember, homozygotes have two occurrences
for Population 1 of Orchis isozymus:
Slow = 23/30 = 0.77 = p
Fast = 7/30 = 0.23 = q
(p + q must add up to 1.0)

12. Wright’s Fixation Index, Fst
Calculate heterozygosity = 2pq
Sum heterozygosity for all three populations of each species
ex. Hs for O. isozymous =  [2pq]=0.353 n
3. Calculate expected heterozygosity, Ht, if all populations were part of one, larger one
Ht = 2[mean p][mean q]
4. Calculate Wright’s Fixation Index, Fst
Fst = (Hs - Ht ) / Ht
Fst<0.01 means little divergence
Fst>0.1 means great divergence