Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Chapter 21, Problem 25P
In a population of infinite size, three loci A, B, and C have two alleles each. Alleles A1, B1, and C1 are found in 1% of the population at a particular moment in time, and each has beneficial effects on the organisms’ fitnesses as compared to the other allele of that locus (A2, B2, and C2, respectively). The relative fitnesses of the three possible genotypes at each of these loci is:
The frequencies of alleles A, B, and C over thousands of generations is shown in the following graph:
| a. | Which line (blue, red, or green) corresponds to A1? B1? C1? |
| b. | Why does the allele represented by the red line go to fixation more quickly than that represented by the green line? |
| c. | Why does the allele represented by the blue line go to fixation more slowly than the alleles represented by either the red or green lines? |
| d. | Suppose the population only had 1000 individuals. Discuss how this change in |
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An autosomal locus has alleles A and a.
The allele frequencies in a population at Hardy Weinberg equilibrium are
p = Freq(A) = 0.5
q = Freq(a) = 0.5
What is the frequency of homozygous wild-type (AA) in this population?
Enter a single number between 0 and 1, for example, 0.33
In a population of flowers growing in a meadow, C1C1 and C2C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with ff (C1)(C1) = 0.8 and ff (C2)(C2) = 0.2. Flowers that are C1C1C1C1 are yellow, orange flowers are C1C2C1C2, and C2C2C2C2 flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C1C1C1C1 = 0.30, C1C2C1C2 = 0.60, and C2C2C2C2 = 1.0.
A. Assuming the population begins in H−WH−W equilibrium, what is C1C1 allele frequency after one generation of natural selection?
B.Assuming the population begins in H−WH−W equilibrium, what is C2C2 allele frequency after one generation of natural selection?
C.
In corn, yellow kernel color is governed by a dominant allele for white color, W, and by its recessive allele, w, . A random sample of 100 kernels from a population that is in equilibrium reveals that 9 are yellow and 91 are white. What are the frequencies of the yellow and white alleles in this population? What is the percentage of the heterozygotes?
Chapter 21 Solutions
Genetics: From Genes to Genomes
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