Download Population Genetics

 The
science of genetic change in
populations.
 Population-
interbreeding single-species
group

individuals of the same species, living in the
same place at the same time
 Populations
evolve.
are the smallest unit that can
 As
a change in the prevalence of certain
traits in a population over several
generations
 Evolution is only apparent when a population
is tracked over time



Spontaneous mutations may produce new traits
Segregation & independent assortment produce
variations in gametes & offspring
Genes are passed through gametes from parents
to offspring
 Theory
developed in the 1940’s
 Includes genetics and evolution
GENE
POOL = where all
members of the next
generation get their
genes!
When allele frequencies
in a population change
over generations,
evolution is occurring at
its smallest scale.
Species
distributed over
a geographic range –>
have different gene
pool
THAN
Species localized 
due to water, islands,
mountains etc.!!!
1.
2.
3.
4.
5.
genetic drift
bottleneck effect
founder effect
gene flow
mutation
A
change in the gene pool of a
small population due to chance!
Ex: flipping coin 10X
Type
of genetic drift colonization of a new location by
a small number of individuals

small size, less representative of
the gene pool.
 Fertile
individuals move into or out of a
population
 Gametes are transferred between
populations.
Allele
frequency
with ONLY sexual
reproduction
involved!
NO OUTSIDE
AGENTS
p = dominant
q = recessive
2pq = heterozygous
p+q=1
p2 + 2pq + q2 = 1
1.
very large population
2. population is isolated
3. mutations (changes in
genes) do not alter the
gene pool
4.
mating is random
5. all indiv. Are equal in
reproductive success
NO NATURAL SELECTION
OCCURS!
Conditions
rarely met by a
natural population
Gives us a basis to compare
nonevolving population vs.
actual ones with gene pools that
are changing!