Transcript After graduation, you and 19 friends build a raft, sail to a deserted

You have a population of mice that you
are breeding in the lab. There are 132
mice in the population. 48 of them are
white, a recessive trait.
What is the frequency of the recessive
allele?
48/132 = .36
√.36 = .6
You have a population of mice that you
are breeding in the lab. There are 132
mice in the population. 48 of them are
white, a recessive trait.
What is the frequency of the
homozygous dominant genotype?
q = .6
p = 1-.6 = .4
P2 = .16
You have a population of mice that you
are breeding in the lab. There are 132
mice in the population. 48 of them are
white, a recessive trait.
What is the frequency of the
heterozygous genotype?
2pq = 2 x .4 x .6
2pq = .48
After graduation, you and 24 friends build a
raft, sail to a deserted island, and start a new
population, totally isolated from the world.
One of your friends carries (is heterozygous
for) the recessive cf allele, which in
homozygotes causes cystic fibrosis.
Assuming that the frequency of this allele
does not change as the population grows,
what will be the instance of cystic fibrosis on
your island?
25 people.
One person carries cf.
49 alleles are dominant, 1 allele is
recessive.
q = 1/50 = .02
p = 49/50 = .98
q2 = .02 x .02 = .0004 (or .04%)
If 9% of an African population is born with
a severe form of sickle-cell anemia (ss),
what percentage of the population will be
more resistant to malaria because they
are heterozygous(Ss) for the sickle-cell
gene?
q2 = .09
q = .3
p = .7
2pq = 2 x .7 x .3 = .42
Wing coloration of the scarlet tiger moth is controlled by
a single gene in an incomplete dominance pattern.
Data was collected for 1612 individuals.
White-spotted (AA) =1469
Intermediate (Aa) = 138
Little spotting (aa) =5
Calculate the following frequencies for this population:
A=
a=
AA =
Aa =
aa =
Wing coloration of the scarlet tiger moth is controlled by
a single gene in an incomplete dominance pattern.
Data was collected for 1612 individuals.
White-spotted (AA) =1469
Intermediate (Aa) = 138
Little spotting (aa) =5
Calculate the following frequencies for this population:
A = 3076/3224 = .954
a = 148/3224 = .046
AA = 1469/1612 = .911
Aa = 138/1612 = .085
aa = 5/1612 =.003
57 high school students at Coral
Shores were surveyed to see if
they could taste the chemical
PTC. 14 of them could not.
What are the allele frequencies
in the population?
q2 = 14/57 = .25
q = .5
p = .5
57 high school students at Coral
Shores were surveyed to see if
they could taste the chemical
PTC. 14 of them could not.
What are the genotype
frequencies in the population?
q2 = .25
2pq = .5
p2 = .25
57 high school students at Coral
Shores were surveyed to see if they
could taste the chemical PTC. 14 of
them could not.
If the surveyed students are
representative of the population,
how many of the 743 students at
the school would you expect will be
able to taste PTC?
If the surveyed students are
representative of the
population, how many of the
743 students at the school
would you expect will be able to
taste PTC?
.75 x 743 = 557
If a specific, recessive allele is
selected against, what would
you expect to see in the allele
frequencies over several
generations?
q would decrease
p would increase
If a specific, recessive allele is
selected against, would you
expect that allele to be lost from
the population?
No. Carriers would pass
the allele to subsequent
generations.
If a specific, dominant allele is
selected against, what would
you expect to see in the allele
frequencies over several
generations?
p would decrease
q would increase
If a specific, dominant allele is
selected against, would you
expect that allele to be lost from
the population?
Yes. There are no carriers.
The allele may be
eliminated over time.
If there is an advantage to being
heterozygous, what effect would
this have on the allele
frequencies of the population?
q would be higher than if there was
no benefit to being heterozygous
How would immigration and
emigration effect the allele
frequencies of an established
population?
It would change the frequencies of
the alleles in the gene pool.
Equilibrium would eventually be
reestablished, but the frequencies
would probably be different.
How does selective mating
effect the allele frequencies
within a population?
The frequency of the selected FOR
allele would increase.
The frequency of the selected
AGAINST allele would decrease.
If a population is small and
isolated, what might you expect
to see in the allele frequencies?
Random chance may cause
aWhat
shiftisinthis
frequencies.
process called?
Either allele could become
more
prominent.
Genetic Drift
What is natural selection?
What is artificial selection?
What animals are currently
undergoing artificial selection?
What are some of the sideeffects of artificial selection?