•http://learn.genetics.utah.edu/content/labs/gel/
Chapter 4
Population Genetics
Diversity Within Versus Diversity Among Populations
Orchis
O. isozymus
O. polyzymus
O. isozymus
O. polyzymus
Your Goal
• apply population genetics concepts to
conservation planning
• specifically, if you have funding to save
only four wetlands, which ones will it be?
Review this demonstration!
• http://learn.genetics.utah.edu/content/labs/gel/
Determine allele frequencies
Determine frequencies of “fast” and “slow”.
1. tally the number of alleles among the 15
individuals
2. divide it by the total number of alleles
present in the population.
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)
Wright’s Fixation Index, Fst
1. Calculate heterozygosity = 2pq
2. 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