Concept explainers
Assortative mating
a. affects genotype frequencies expected under Hardy–Weinberg equilibrium.
b. affects allele frequencies expected under Hardy–Weinberg equilibrium.
c. has no effect on the genotypic frequencies expected under Hardy–Weinberg equilibrium because it does not affect the relative proportion of alleles in a population.
d. increases the frequency of heterozygous individuals above Hardy–Weinberg expectations.
Introduction:
Assortive mating involves matting of phenotypically similar individuals. It is a type of non-random mating those results in the frequencies of particular genotypes and the allelic frequency of that population is different from the Hardy–Weinberg principle.
Answer to Problem 1U
Correct answer:
Assortive mating occurs when individuals choose their mates based on their resemblance each other on the basis of certain phenotype that upset the Hardy–Weinberg principle. Therefore option a. is correct.
Explanation of Solution
Reason for the correct statement:
Assortive matting involves mates of similar phenotype. Its effect is limited to genes that influence the phenotype and its impact on the overall population is limited by mating that is otherwise random.
Option a. is given as “affects genotype frequencies expected under Hardy–Weinberg equilibrium”.
As, the random mating is a requirement of genetic equilibrium whereas assortive mating affects the genotypic frequency within individuals as it select the mate based on similar traits and does not support the Hardy–Weinberg principle for genetic equilibrium.
Hence, the option a is correct.
Reasons for incorrect statements:
Option b. is given as “affects allele frequencies expected under Hardy–Weinberg equilibrium”.
Assortive mating affects the genotypic frequency not the allelic frequency as expected under Hardy-Weinberg equilibrium. So it is a wrong answer.
Option c. is given as “has no effect on the genotypic frequencies expected under Hardy–Weinberg equilibrium because it does not affect the relative proportion of alleles in a population”.
Assortive mating occurs between the individual of similar traits it affects the genotypic frequency and not the allelic frequency in a population as expected under Hardy-Weinberg equilibrium. So it is a wrong answer.
Option d. is given as “increases the frequency of heterozygous individuals above Hardy–Weinberg expectations”.
Assortative mating results when individuals mate with partners that are like themselves in certain phenotypic characters, it results in fewer heterozygotes than Hardy-Weinberg predicts. So it is a wrong answer.
Hence options b, c, and d are incorrect.
Assortative mating affects genotype frequencies expected under Hardy–Weinberg equilibrium.
Want to see more full solutions like this?
Chapter 20 Solutions
BIOLOGY VOL. II
- How 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_forwardA population has 25 individuals of genotype AA, 25 individuals of genotype aa, and 50 individuals of genotype Aa. Is this population in Hardy Weinberg equilibrium? Why or why not? Group of answer choices A. No because p2 + 2pq + q2 does not equal 1 B. Yes because p2 + 2pq + q2 = 1 C. Yes because the genotype frequencies match HW expectations based on allele frequencies D. No because there are more heterozygotes than expected under Hardy Weinberg E. No because there are fewer heterozygotes than expected under Hardy Weinbergarrow_forwardI. A population called the founder generation, consisting of 2000 AA individuals, 2000 Aa individuals, and6000 aa individuals is established on a remote island.Mating within this population occurs at random, thethree genotypes are selectively neutral, and mutationsoccur at a negligible rate.a. What are the frequencies of alleles A and a in thefounder generation?b. Is the founder generation at Hardy-Weinbergequilibrium?c. What is the frequency of the A allele in the secondgeneration (that is, the generation subsequent to thefounder generation)?d. What are the frequencies for the AA, Aa, and aagenotypes in the second generation?e. Is the second generation at Hardy-Weinbergequilibrium?f. What are the frequencies for the AA, Aa, and aagenotypes in the third generation?arrow_forward
- within a randomly mating population of beagles, the homozygous presence of the recessive allele 'm' causes lemon color pattern, while the presence of dominant allele M produce a tri-color pattern. A survey was made in a town and of the 167 tagged, 83 has lemon color. Question: Determine: a. the frequency of the dominant allele; b. number of animals have the dominant allele; c. number of animals that are heterozygous; d. number of animals that have homozygous recessive gene.arrow_forwardIn a population at Hardy-Weinberg equilibrium, 190 out of 1000 individuals have polydactyly. Note that the trait is dominant. a. What is the frequency of the dominant and recessive alleles? b. How many are expected to be heterozygotes for the trait? c. How many are expected to be homozygous dominant?arrow_forwardConsider a gene with two alleles, C and M. The table below describes fitness for different genotypes in two populations. Fitness CC CM MM Population 1 1.0 1.0 0.6 Population 2 0.9 0.9 1.0 Which of the following is true based on this table? A.) C is recessive and M is dominant B.) M is recessive and C is dominant C.) Neither allele is dominant D.) C is dominant in population 1 and M is dominant in population 2arrow_forward
- A. The Hardy-Weinberg Equilibrium is important because it serves as a null hypothesis in studies that evaluate evolution of species. it explains how evolution works. it predicts how allele and genotype frequencies will change over time. it clarifies how traits are passed from parent to offspring. B. Hardy-Weinberg Equilibrium occurs frequently in natural populations. predicts changes in allele and genotype frequencies. is inhibited by random mating. assumes large population sizes.arrow_forwardA population of mice contains 20 animals Show work here: with white tails and 30 animals with grey tails. Grey tails are the dominant trait. a. What is the frequency of the white allele? b. What is the frequency of the grey allele? c. What is the frequency of heterozygotes? d. What is the frequency of mice homozygous for the grey allele?arrow_forwardAssuming a population is in Hardy-Weinberg equilibrium, an increase in the frequency of the p(A) allele from 0.6 to 0.9 would result in which of the following outcomes? a. A decrease in the number of homozygous dominant individuals within the population b. A decrease in the number of homozygous recessive individuals within the population c. An increase in the number of homozygous recessive individuals within the population d. An increase in the number of heterozygotes within the population e. No change in genotypic frequency within the populationarrow_forward
- What is the expected frequency of heterozygotes in a population with allelic frequencies xand y that is in Hardy–Weinberg equilibrium?a. x + yb. xyc. 2 xyd.( x − y)2arrow_forwardTheHardy-Weinberg principle states that:a.genotypic changes will result in phenotypic changes.b.phenotypic changes will result in genotypic changes.c.allelic frequencies within a population will not change unless certainconditions are met.d.allelic frequencies within a population will change unless certainconditions are met.e.none of the choices apply.arrow_forwardA gene has two alleles A (frequency = p) and a(frequency = q). If a population is at Hardy-Weinbergequilibrium, develop mathematical expressions interms of p and q that predict the following matingfrequencies:a. Between two AA homozygotesb. Between two aa homozygotesc. Between two Aa heterozygotesd. Between an AA homozygote and an aa homozygotee. Between an AA homozyote and an Aa heterozygotef. Between an aa homozygote and an Aa heterozygote Considering your answers to parts (a)–(f):g. Do the six possibilities listed account for all possible matings? How would you know whether this istrue mathematically? Demonstrate this latter pointby setting p equal to an arbitrary number between0 and 1 such as 0.2.h. Can you develop a simple, general rule for calculating the mating frequencies between individualsof the same genotype versus the mating frequencies between individuals of different genotypes?i. If the population is equally divided between malesand females, what proportion of all matings…arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning