GENETIC ANALYSIS: INTEGRATED - ACCESS
3rd Edition
ISBN: 9780135349298
Author: Sanders
Publisher: PEARSON
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Textbook Question
Chapter 20, Problem 6P
Genetic drift, an evolutionary process affecting all populations, can have a significant effect in small populations, even though its effect is negligible in large populations. Explain why this is the case.
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Chapter 20 Solutions
GENETIC ANALYSIS: INTEGRATED - ACCESS
Ch. 20 - 20.1 Compare and contrast the terms in each of the...Ch. 20 - In a population, what is the consequence of...Ch. 20 - 20.3 Identify and describe the evolutionary forces...Ch. 20 - Describe how natural selection can produce...Ch. 20 - Thinking creatively about evolutionary mechanisms,...Ch. 20 - 20.6 Genetic drift, an evolutionary process...Ch. 20 - Over the course of many generations in a small...Ch. 20 - Catastrophic events such as loss of habitat,...Ch. 20 - 20.9 George Udny Yule was wrong in suggesting that...Ch. 20 - 20.10 The ability to taste the bitter compound...
Ch. 20 - Figure 20.6 illustrates the effect of an ethanol ...Ch. 20 - 20.12 Biologists have proposed that the use of...Ch. 20 - 20.13 Two populations of deer, one of them large...Ch. 20 - 20.14 Directional selection presents an apparent...Ch. 20 - 20.15 What is inbreeding depression? Why is...Ch. 20 - 20.16 Certain animal species, such as the...Ch. 20 - Genetic Analysis 20.1 predicts the number of...Ch. 20 - 20.18 In a population of rabbits, and . The...Ch. 20 - Sickle cell disease (SCD) is found in numerous...Ch. 20 - 20.20 Epidemiologic data on the population in the...Ch. 20 - The frequency of tasters and nontasters of PTC...Ch. 20 - Tay-Sachs disease is an autosomal recessive...Ch. 20 - 20.23 Cystic fibrosis (CF) is the most common...Ch. 20 - 20.24 In the mouse, Mus musculus, survival in...Ch. 20 - 20.25 In a population of flowers growing in a...Ch. 20 - Assume that the flower population described in the...Ch. 20 - 20.27 ABO blood type is examined in a Taiwanese...Ch. 20 - 20.28 A total ofmembers of a Central American...Ch. 20 - 20.29 A sample offield mice contains individuals...Ch. 20 - Prob. 30PCh. 20 - Albinism, an autosomal recessive trait...Ch. 20 - 20.32 The frequency of an autosomal recessive...Ch. 20 - 20.33 Evaluate the following pedigree, and answer...Ch. 20 - Evaluate the following pedigree, and answer the...Ch. 20 - The following is a partial pedigree of the British...Ch. 20 - Draw a separate hypothetical pedigree identifying...Ch. 20 - Prob. 37PCh. 20 - 20.38 Achromatopsia is a rare autosomal recessive...Ch. 20 - 20.39 New allopolyploid plant species can arise by...
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- Differentiate genetic drift from genetic shift. What is genotype frequency? How do you get the genotype frequency? Give formula and cite example.arrow_forwardHow Can We Measure Allele Frequencies in Populations? In a population where the females have the allelic frequencies A = 0.35 and a = 0.65 and the frequencies for males are A = 0.1 and a = 0.9, how many generations will it take to reach HardyWeinberg equilibrium for both the allelic and the genotypic frequencies? Assume random mating and show the allelic and genotypic frequencies for each generation.arrow_forwardHow Can We Measure Allele Frequencies in Populations? Drawing on your newly acquired understanding of the HardyWeinberg equilibrium law, point out why the following statement is erroneous: Because most of the people in Sweden have blond hair and blue eyes, the genes for blond hair and blue eyes must be dominant in that population.arrow_forward
- Imagine you are studying a population of finches on one of the Galápagos Islands. You have been recording many of the birds’ physical traits, including the length of both wings. You observe that for 80% of individuals measured, the length of the left wing is not significantly different from the length of the right wing (in other words, they are symmetrical). But for about 20% of birds measured, the wing lengths are asymmetrical. This distribution is true from generation to generation. Suddenly, a rare 5-day windstorm takes over the island. After the storm, you spend the next several days netting each bird on the island that survived the storm. You discover that 85% of the birds with symmetrical wings survived the storm, whereas only 5% of the birds with asymmetrical wings did. a. Propose a hypothesis to explain this observation. b. If such storms become increasingly common due to changes in climate, how might you expect the population to change over time with respect to wing symmetry?arrow_forwardExplain the role of genetic drift in shaping the genetic landscape of populations. Compare and contrast genetic drift with other evolutionary forces, such as natural selection, highlighting their respective contributions to population genetic variation.arrow_forwardLet’s suppose the mutation rate for converting a B allele into a b allele is 10–4. The current allele frequencies are B = 0.6 and b = 0.4. How long will it take for the allele frequencies to equal each other, assuming that no genetic drift takes place?arrow_forward
- Under what scenaries is genetic drift most potent as an evolutionary process? how do factors like population size and initial allele frequences affect likelihood of an allele being lost from a population (or becoming fixed)?arrow_forwardWhy the impact of genetic drift is more significant in smaller population?arrow_forwardLet’s say that a large ancestral population of really cool organisms is subdivided, by a geological cataclysm, into a large number of isolated, ideal populations, each of size 100. Suppose we’re interested in an autosomal locus with two alleles, A and a, with p = the frequency of A = 0.75 in the ancestral population, as well as in each newly isolated population. Assume that genetic drift is the only evolutionary force operating. a) What is the average allele frequency of A in the populations after 5, 10, and 100 generations? b) What allele frequencies of A do you expect to find within each population at equilibrium, and what percentage of the populations will have each specific allele frequency? (recall various simulations we did/could do of genetic drift in several populations) c) What is the average Inbreeding Coefficient (or Fixation Index) F for each population after 20 generations? Assume F = 0 for all individuals in the ancestral population. d) Redo (c), assuming an initial…arrow_forward
- The forward mutation rate for piebald spotting in guinea pigs is 8 × 10-5;the reverse mutation rate is 2 × 10-6. If no other evolutionary forces areassumed to be acting, what is the expected frequency of the allele forpiebald spotting in a population that is in mutational equilibrium?arrow_forward"Natural Selection Is a Major Force Driving Allele Frequency Change". Explain how ?arrow_forwardIn many large mammal populations, highways can be barriers to movement - individuals rarely cross them. One solution to this problem has been to install overhead bridges for wildlife to safely cross. The goal is to increase gene flow between the populations on either side of the highway. Which of the following would you expect to see if the bridge is successful in its goal? O Higher levels of drift would occur after the bridge is installed The two populations would have different mutation rates O Both populations would decrease in size O The two populations would become more genetically similar O We would see fewer heterozygotes in both populationsarrow_forward
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