Evolution – Biology 4250
Hardy-Weinberg Problems

**SHOW ALL YOUR WORK** ! ! ! Round answers to the nearest two
significant digits past the

decimal point. Unless otherwise specified, assume populations are in a
fictitious H-W equilibrium.

1. In a population with 2 alleles for a particular locus (D and d), the
frequency of the D allele is 0.91.

a) What is the frequency of the d allele?

b) What is the frequency of homozygous dominant individuals in the population?

c) What is the frequency of homozygous recessive individuals in the population?

d) What is the frequency of heterozygotes in the population?

2. The fraggles are a population of mythical, mouselike creatures that live in
underground tunnels and

chambers beneath a large vegetable garden that supplies their food. They can
reproduce VERY quickly!

Of the 154 fraggles currently in this population, 93 have green fur and 61 have
gray fur. Green fur is

controlled by a dominant allele F and gray fur by a recessive allele f.

a) What is the frequency of the gray allele f?

b) What is the frequency of the green allele F?

c) How many fraggles are heterozygous (Ff)?

d) How many fraggles are homozygous recessive (ff)?

e) How many fraggles are homozygous dominant (FF)?

3. One summer, a dust storm blankets the usually green garden of the fraggles in
gray for a short period

of time. Under these conditions, the green fraggles become very visible to the
Gorgs, monstrous beasts

who tend the gardens and try to kill the fraggles to protect their crops. The
gray fraggles, however,

blend into the dusty background and find that they can easily steal radishes
from the garden. How

might this event affect microevolution in this population of fraggles, at least
temporarily? Remember,

the fraggles can reproduce very quickly!

4. In a population that is in Hardy-Weinberg equilibrium, 16% of the individuals
exhibit the recessive

trait (ss).

a) What is the frequency of the dominant allele (S) in the population?

b) What percent of the population possesses the dominant allele (S)?

5. The frequency of children homozygous for a recessive lethal allele is about
1/25,000. What proportion

of the population are carriers of the lethal
allele?

6. Coat color in sheep is determined by a single gene. Allele B, for white wool,
is dominant over allele b,

for black wool. We have followed a population of sheep for two years. Below are
the statistics we have

compiled.

Year 1 Year 2

White sheep
489 682

Black sheep
128 176

Total number of individuals 617
858

a) Determine the frequency of both alleles (B & b) in year 1.

b) Determine the frequency of both alleles (B & b) in year 2.

c) Is this population in Hardy-Weinberg equilibrium? Why or Why not?

d) If the allelic frequencies for a particular gene in a population remain
constant from year to year,

what does this mean about the evolution of wool color in this population of
sheep?

7. The formation of methylmercaptan from ingested asparagus is a recessive
trait. To find out if

you are a methylmercaptan forming individual, simply eat a serving of asparagus
and wait

approximately 20 minutes before urinating. You will be able to detect a very
distinctive odor if you

have inherited the ability to form methylmercaptan. What percent of the
population would be

homozygous recessive for this trait if it is known that 30% are homozygous
dominant?

8. In a particular species of flower, C1 codes for red flowers, C2 codes for
white, with the heterozygous

individuals being pink.

a. If the frequency of pink individuals in the population was .5163, would you
be able to estimate the

frequencies of the individual alleles in the population? Why or why not?

b. If the frequency of red individuals in the population was .737, what would
the estimated frequency of

pink and white individuals be in this same population?

c. There is a pollinator introduced into the population of flowers that prefers to visit white flowers

8 to
1 compared to red flowers,
and visits red and pink flowers equally. Starting from the frequencies

in b.
(above), and assuming all
pollinated flowers participate equally in generating the next generation,

what
would the frequencies of
the C1 and C2 alleles be in the next generation?

9. Suppose the number of red, pink and white individuals in another population
of flowers was 398, 789,

and 444 respectively. Could this population be said to be in H-W equilibrium?
SHOW YOUR WORK!