PREWORK
• LIST the 5 conditions necessary for the Hardy-Weinberg equation
• DEFINE: genetic drift, fixation, bottleneck, founder effect, gene flow
• REVIEW: evolution, the three types of natural selection
the set of all the genetic information in a
specific population of a species
p: the frequency of the dominant allele
: the frequency of the recessive allele
p+q=1
p: the frequency of the dominant allele
: the frequency of the recessive allele
What is the probability that a
dominant allele would be
drawn from the gene pool?
What is the probability that
two dominant alleles would
be pulled from the gene
pool?
What is the probability that
two recessive alleles would
be pulled from the gene
pool?
What is the probability that
one dominant and one
recessive allele would be
pulled from the gene pool?
2
p
+ 2pq +
2
q
=1
Mathematically show how to derive the
Hardy-Weinberg equation from p + q = 1
2
p
+ 2pq +
2
q
=1
p2 : the frequency of homozygous dominant
q2 : the frequency of homozygous recessive
2pq: the frequency of heterozygous
16% of the population cannot taste the bitter chemical PTC.
The ability to taste PTC is dominant.
1. What percent of individuals are tasters?
2. What is the frequency of the dominant and recessive allele?
3. What percent of individuals are heterozygous?
64% of the population has the dominant trait of a widow’s
peak compared to the recessive straight hairline.
1. What is the frequency of the dominant and recessive allele?
2. What percent of individuals are homozygous dominant?
3. What percent of individuals are heterozygous?
4. What percent of individuals are homozygous recessive?
The delta-32 mutation (caused by a recessive gene) gives humans
protection to the HIV virus. Homozygous recessive individuals are
immune to the virus, while heterozygous individuals are less
susceptible to it. The recessive allele frequency in a small town in
Europe is 20%.
If the town had a population of 3,800 people,
1. about how many people are immune to HIV in town?
2. about how many people are less susceptible to HIV?
3. about what percent of the town has some sort of protection against
HIV?