Hardy Weinberg population genetic problems:
1. A certain homozygous recessive geneotype occurs in 4% of a
population. What is the frequency of its two alleles, T and t?
2. What percentage of the population is heterozygous (Tt) ?
3. In a certain species of plant where red and white flowers are
determined by a single pair of alleles, R (red) and r (white), a grower counted
90 white flowering plants in a field of 1000. If random pollination is occurring,
what proportion of the field is heterozygous?
4. In the United States, 16% of the population is Rh-, due to a
homozygous recessive pair of alleles. From this data, determine:
a. the frequency of the recessive gene
b. the frequency of the dominant gene
c. the percentage of heterozygotes in the population
5. The frequency of a particular recessive gene is 0.5 .
a. What percentage of the population will be homozygous recessive?
b. What are the percentages of each of the three genotypes in the
population?
6. A certain gene (k) is recessive; the dominant gene (K) is one
of the genes necessary to produce chlorophyll in plant leaves. In a particular
variety of corn, 36% of the seedlings are found to lack chlorophyll and appear
yellow when they sprout, then die. Determine:
a. the frequency of K
b. the frequency of k
c. the percentage of individuals that are Kk
7. About 1 in 10,000 Caucasians born in the U.S.A. have the
homozygous recessive condition where they lack the ability to produce the
enzyme PKU. Without treatment, this is a fatal condition. This is a fairly difficult problem.
a. What is the frequency of the recessive gene?
b. What percentage of individuals are heterozygous?
8. Native Africans who immigrated to the American Colonies as
slaves had an estimated sickle cell allele frequency of .25. Assume that all of
the homozygous recessive children died before producing offspring , calculate
the percentage of homozygous dominant and heterozygous individuals in that
African-American founders population. What was the percentage that died?
(Ignore deaths due to malaria as the US is not in a malaria zone).
9. In a population of cats containing 4 with white fur, 64 with
solid brown fur, and 32 with tan fur, what is the white gene frequency?
10. Explain the
difference between an adaptation and the term "natural selection".
11. If evolution is
defined as "change through time", what really is
changing during biological evolution?
12. Is the global human gene pool in equilibrium? Why or why not? Cite at least three reasons.
13. Darwin could not
explain the origins of the variations he observed, you can, what are they?
14. In wooba-wooba
plants, petal color is co-dominant. The three petal phenotypes are black, grey and white. The black allele frequency is greater
than the white allele frequency.
48% of the population is grey.
What percent of the population should have the elegant
black petals?
THINK (start with a punnet square, fill in what
information is given and then solve the entire square) SHOW YOUR WORK.
15. If 30% of a
population shows a recessive phenotype, how would you figure out p and q? Obviously you do not have access to
calculators so leave your work in unfinished form. Again use a punnet square, remember I am asking only for p
and q.
16. Define and
give an example of the following terms:
gene flow-
genetic drift-
17. Within an
isolated population of 10,000 rats (that are in equilibrium) 3600 individuals
have white fur, a homozygous recessive trait. How many rats should be homozygous dominant for their fur
color? Show work. yes, start with
your punnet square.
18. Gene frequencies
will NOT change if a population's gene pool is in equilibrium. Give three examples of these conditions
that will keep a population in equilibrium.
19. What factors/circumstances favored the dark allele frequency in
the peppered moth gene pool to increase? What factors/circumstances favored the light allele ifrequency
in the peppered moth gene pool to increase?
20. The following
list is a gene pool that is in equilibrium of a very small
breeding population of nerdy birdys (I made it up) for the dominant trait, Albinism.
A A A A a a A a A A A a a a a a
What is the predicted percent of the F1 that will have the albino
phenotype? Show work.
21. Explain how the
use of antibiotics has actually resulted in antibiotic resistant bacteria now
becoming a serious health concern.