Q6.1. What is the founder effect? Sampling error that occurs during the establishment of a new population by a small number of migrants Natural selection that acts on the founders of a new population in their new, different environment The frequencies of alleles in a population changing slowly over generations due to chance events A period of rapid population growth that immediately follows some population bottlenecks Submit Q6.2. Which of the following statements about genetic drift and population size is TRUE? If a population is large enough, it will not experience any genetic drift. The larger a sample is, the less likely it is similar to its source population. A population can lose genetic diversity when its size is drastically reduced. The effects of genetic drift are less pronounced in very small populations. Submit

Q6.1. What is the founder effect? Sampling error that occurs during the establishment of a new population by a small number of migrants Natural selection that acts on the founders of a new population in their new, different environment The frequencies of alleles in a population changing slowly over generations due to chance events A period of rapid population growth that immediately follows some population bottlenecks Submit Q6.2. Which of the following statements about genetic drift and population size is TRUE? If a population is large enough, it will not experience any genetic drift. The larger a sample is, the less likely it is similar to its source population. A population can lose genetic diversity when its size is drastically reduced. The effects of genetic drift are less pronounced in very small populations. Submit

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter19: The Evolution Of Populations

Section: Chapter Questions

Problem 6RQ: Which of the following populations is not in Hardy- Weinberg equilibrium? a population with 12...

See similar textbooks

Similar questions

The original source of new alleles, upon which selection operates,is mutation, a random event that occurs without regard to selectionalvalue in the organism. Although many model organismshave been used to study mutational events in populations, someinvestigators have developed abiotic molecular models. Soll et al.(2006. Genetics 175:267–275) examined one such model to studythe relationship between both deleterious and advantageousmutations and population size in a ligase molecule composed ofRNA (a ribozyme). Soll found that the smaller the population ofmolecules, the more likely it was that not only deleterious mutationsbut also advantageous mutations would disappear. Whywould population size influence the survival of both types ofmutations (deleterious and advantageous) in populations?
Three basic predictions underlie genetic drift in populations: (1) As long as the population size is finite,some level of genetic drift will occur; thus, withoutnew mutations, all variation will drift either to fixationor to loss. (2) Drift happens faster in small populationsthan in large populations. (3) The probability that anallele is fixed (goes to a frequency of 1.0) is equal toits initial frequency (p) in the population, while itsprobability of loss from the population due to drift isequal to 1 − p. Given these three predictions:a. What is the allele frequency of a new autosomalmutation immediately after it occurs in a diploidpopulation of size N = 100,000?b. What is the allele frequency of a new autosomalmutation immediately after it occurs in a diploidpopulation of size N = 10?c. In which population does the new mutation have ahigher probability of going to fixation by chancewith genetic drift?
Exercse 2 #1 - In what populations do we see the high frequencies (above 80%) of the allele associated with lighter pigmentation? O Chinese O African O Japanese O Bangladeshi V French O Mongolian V Italian V German O Indian O Turkish Indonesian Question 2 Exercse 2 #4 - Why might some light-skinned populations, such as the Japanese, be missing the F374 allele? O Some populations, such as Japanese, are only light-skinned because they avoid tanning. O This allele does not cause depigmentation. O There have been multiple, different mutations that have produced light skin in different populations. The sampling of Japanese in this study probably did not capture the true incidence of the F374 allele in the population.
Q5.3. Someone has handed you the following graph of changes in the frequency of one allele in a population over time. Based on the graph and without any other information, which of the following is most likely true? Allele Frequency 1.0 + 0.75 0.50 0.25 0.00 10 Time (generation) 20 The allele does not offer any fitness advantage and the population is small. The allele does not offer any fitness advantage and the population is large. The allele offers a selective advantage and the population is small. The allele was introduced at a very low frequency and the population is large. 30
Small population size causes genetic drift because ofchance sampling of different alleles from one generation to the next. We can predict how much geneticdrift occurs for a given population size using binomialsampling statistics. With a population of size N, wecan estimate that 95% of the time the allele frequency(p) in the next generation will be withinthe confidence interval of p ± 1.96 (√p(1 − p)2N ),where p(1 − p)2Nis an estimate of the statistical variancein allele frequencies from one generation to the nextwith random sampling of 2N alleles each generation. a. What is the confidence interval for p = 0.5 whenN = 100,000?b. What is the confidence interval for p = 0.5 whenN = 10?c. How are the results in parts (a) and (b) related tothe consequences of a population bottleneck?
Q6.8. Imagine a population evolving by genetic drift, in which the frequency of allele K is 0.3. What is the probability that at some point in the future allele K will drift to a frequency of 1.0? Express your answer as a number between 0 and 1. (Hint: Remember the exercise you did in Section 3 - Size Matters, where you explored how the probability of fixation is dependent on an allele's initial frequency.)
Q7. Someone has handed you the following graph of changes in the frequency of one allele in a population over time. Based on the graph and without any other information, which of the following is most likely true? 1.0 + 0.75 + Allele Frequency 0.50 0.25 + 0.0 0,00 10 20 30 Time (generation) O The allele does not offer any selective advantage and the population is small. O The allele does not offer any selective advantage and the population is large. O The allele offers a selective advantage and the population is large. The allele was introduced at a very low frequency and the population is large.
@ 2 W S Rehpogs are mythical creatures. They are small and not very smart. Rehpogs live on the ground in a flat, warm habitat. Their fur texture and color ranges from thick purple fur to thin pink fur, depending on allele distribution. The dominant fur allele (R) codes for thick purple fur. The recessive allele (r) codes for thin pink fur. REMEMBER: a phenotype (fur color) is the physical expression of a genotype (two- letter code for the alleles present in that individual). Each individual has two alleles for fur color: X RR genotype is homozygous dominant = Thick purple fur phenotype Rr genotype is heterozygous = Thick purple fur (because of the presence of one dominant allele) rr genotype is homozygous recessive = Thin pink fur (because of the absence of a dominant allele) For the purposes of this experiment, Rehpogs mate once per year and produce two offspring each year. Rehpogs are monogamous, faithful and fertile. # 3 e d C C $ 4 r f V % 5 t g Oll 6 b y h & 7 O 8 n JL u i j O L m…
ajor G Population Evolution FIB with Using the two Hardy-Weinberg equations, calculate the allelic and genotypic frequencies. Using the information provided in the chart below and the Hardy - Weinberg equations, calculate the genotypic frequencies for this population. = the frequency of the dominant allele the frequency of the recessive allele p = the frequency of the homozygous dominant genotype 2pq = the frequency of the heterozygous genotype q 2 = the frequency of the homozygous recessive allele 1 = the total population b. 2 %3D %3D %3D Genotype Number Genotypic frequency AA 490 49% Aa 420 42% 90 aa TOTAL 1000 100% p+ q = 1 [allelic frequency] p2 + 2pq + q 2 = 1 [genotypic frequencies] q= 0.3 1. Given the aa genotypic frequency, what is q [allelic frequency]? q2 = 0.09 %3D what is the allelic frequency for p? p = 0.7 2. Given q = 0.3 3. What is the AA frequency? 0.49 4. What is the Aa frequency?
5) A mutant red coat color allele (Yr) arises in island B and is present in the adult population in a heterozygous individual in the population of 117 adults of year 2000. Yr is recessive to the other alleles at the Y locus. What is the probability (p) that, purely by the action of genetic drift, the allele will rise to fixation (reaching a frequency of 1.0) at some time in the future? (A) 0.0 < p < 0.2 (B) 0.2 < p < 0.4 (C) 0.4 < p < 0.6 (D) 0.6 < p < 0.8 (E) 0.8 < p < 1.05 6) For the same genetic scenario, what if the single red allele arose in the island A and was present by 1990 in a heterozygous individual, one of a population 12 individuals. Would this red mutant allele have a better or worse chance of rising to fixation relative to the island B population of problem 5? (A) red allele more likely to reach fixation in A island beginning in 1990 compared to B island beginning in…
18. Would you expect to see a greater Aq from one genera- tion to the next in a population with an allele frequency (q) of 0.2 or in a population with an allele frequency of 0.02? Assume relative fitness is the same in both popu- lations and that the equilibrium frequency for q is 0.01.
O Question 3. Is the population in H-W equilibrium? Observed genotype numbers A₁A1 =40 O Question 4: Is the population in H-W equilibrium? Observed number of each genotype ■ ● A1A2 =20 A2A2 = 40 ● A₁A1=36 A1A2=28 A₂A2=36 Note that raw numbers are given. The question is whether observed frequencies = expected frequencies. You must first compute the genotype frequencies.