Download Hardy-Weinberg Law

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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.
AAAAaaAaAAAaaaaa
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.