Genetics: From Genes to Genomes, 5th edition
5th Edition
ISBN: 9780073525310
Author: Leland H. Hartwell, Michael L. Goldberg, Janice A. Fischer, Leroy Hood, Charles F. Aquadro
Publisher: McGraw-Hill Education
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Chapter 20, Problem 25P
You have identified an autosomal gene that contributes to tail size in male guppies, with a dominant allele B for large tails and a recessive allele b for small tails. Female guppies of all genotypes have similar tail sizes. You know that female guppies usually mate with males with the largest tails, but the effects of population density and the ratio of the sexes on this preference have not been studied. You therefore place an equal number of males in three tanks. In tank 1, the number of females is twice the number of males. In tank 2, the numbers of males and females are equal. In tank 3, half as many females as males are present. After mating, you find the following proportions of small-tailed males among the progeny: tank 1, 16%; tank 2, 25%; tank 3, 30%.
| a. | In your original population (before the animals were placed in the three tanks), 25% of the males have small tails. Assuming that the allele frequencies in males and females are the same, calculate the frequencies of B and b in your original population. |
| b. | Calculate Δq for each tank. |
| c. | If WBB = 1.0, what is WBb for each tank? |
| d. | If WBB = 1.0, is Wbb less than, equal to, or greater than 1.0 for each tank? |
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You are studying a population of giraffes. In this population, one gene (G) controls spot color in
giraffes, which shows incomplete dominance. Individuals with white spots are homozygous gg,
individuals with brown spots are homozygous GG, and heterozygotes have orange spots (Gg). You
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Calculate the observed allele frequencies, using p for the frequency of allele G, and the expected
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chi-square calculation!). For frequencies, report four positions after the decimal. For expected
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Chapter 20 Solutions
Genetics: From Genes to Genomes, 5th edition
Ch. 20 - Choose the best matching phrase in the right...Ch. 20 - When an allele is dominant, why does it not always...Ch. 20 - A population with an allele frequency p of 0.5 and...Ch. 20 - Prob. 4PCh. 20 - Which of the following populations are at...Ch. 20 - A dominant mutation in Drosophila called Delta...Ch. 20 - A large, random mating population is started with...Ch. 20 - Prob. 8PCh. 20 - Prob. 9PCh. 20 - Two hypothetical lizard populations found on...
Ch. 20 - It is the year 1998, and the men and women sailors...Ch. 20 - Prob. 12PCh. 20 - In 1927, the ophthalmologist George Waaler tested...Ch. 20 - Prob. 14PCh. 20 - A gene has two alleles A frequency = p and a...Ch. 20 - Some people can taste the bitter compound...Ch. 20 - Androgenetic alopecia pattern baldness is a...Ch. 20 - Why is the elimination of a fully recessive...Ch. 20 - Tristan da Cunha is a group of small islands in...Ch. 20 - Small population size causes genetic drift because...Ch. 20 - Prob. 21PCh. 20 - A mouse mutation with incomplete dominance t =...Ch. 20 - In Drosophila, the vestigial wings recessive...Ch. 20 - Prob. 24PCh. 20 - You have identified an autosomal gene that...Ch. 20 - In Europe, the frequency of the CF allele causing...Ch. 20 - An allele of the G6PD gene acts in a recessive...Ch. 20 - Explain why evolutionary biologists monitor...Ch. 20 - What is the most straightforward evidence at the...Ch. 20 - In March 2013, the American Journal of Human...Ch. 20 - If you go back 40 generations into your biological...Ch. 20 - In Fig. 21.17, to what part of the world does...Ch. 20 - Predict the DNA sequences at the four nodes...Ch. 20 - A cladogram not drawn to scale for the taxonomic...Ch. 20 - As noted in Fig. 21.22, humans now living in...
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