Q36 - Hardy-Weinberg, Genetic Drift and Fixation Probability in a Body-Color Locus
Following is a description regarding a population of a diploid organism, species A, with a special focus on the locus C that is involved in body color. Based on the given information, indicate whether each of the following statements is true or false.
Using the information and data, determine which of the statements are true or which are false.
A. Information: Species A consists of two color morphs, black and yellow, controlled by a single locus C: the allele CB for the black type and the allele CY for the yellow type. Statement: If the allele CB is completely dominant to the allele CY and the frequency of the yellow type individuals is 9%, the genotype frequency of CBCB is about 70%. Note that the population is assumed to be under Hardy-Weinberg equilibrium.
B. Information: When the body colors of ten species belonging to the same genus with species A were examined, they were all yellow. Statement: In this case, the body color of the ancestral species A just after splitting from these closely related species must have been yellow under a parsimony principle.
C. Information: A small portion of individuals in the population of species A was isolated due to diastrophism (large-scale deformation of Earth's crust) and formed a new population A'. Statement: The drastic inter-generation changes of allele frequency of locus C in population A' can be best explained by natural selection.
D. Information: A slightly deleterious mutation with exactly the same effect on the fitness of an individual independently occurred in both the small population A' and the larger parental population A. Statement: The fixation probability of this mutation is the same in both populations.
Question reproduced from IBO 2020, Theoretical Exam 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)