Concept explainers
Choose the best matching phrase in the right column for each of the terms in the left column.
a. fitness | 1. the genotype with the highest fitness is the heterozygote |
b. gene pool | 2. chance fluctuations in allele frequency |
c. fitness cost | 3. mutations accumulate at a relatively constant rate |
d. allele frequencies | 4. p = 1.0 |
e. heterozygote advantage | 5. ability to survive and reproduce |
f. equilibrium frequency | 6. p and q |
g. genetic drift | 7. event that drastically lowers N |
h. molecular clock | 8. the advantage of a particular genotype in one situation is a disadvantage in another situation |
i. population bottleneck | 9. frequency of an allele at which Δq = 0 |
j. hominins | 10. collection of alleles carried by all members of a population |
k. fixation | 11. Homo sapiens, Neanderthals, and Denisovans |
a.
To determine:
The phrase that describes “fitness” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Fitness in the field of genetics can be described as a term that means ability of an organism to survive and produce offsprings.
Answer to Problem 1P
Correct answer:
Fitness: Ability to survive and reproduce
Explanation of Solution
Fitness is defined as the ability of an organism to survive and reproduce efficiently. It is the ability of an organism to successfully transmit its genetic material (genes) to the next generation.
Thus, the term that describes “ability to survive and reproduce” is fitness.
b.
To determine:
The phrase that describes “gene pool” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Gene pool refer to the collection of alleles or genes that are usually present in an interbreeding population.
Answer to Problem 1P
Correct answer:
Gene pool: Collection of alleles carried by all members of a population
Explanation of Solution
The collection of all the genes or alleles that are found in a particular population is termed as the gene pool. It is an important concept of population genetics as it helps in determining all the alleles that are common in a population.
Thus, the term that describes “the collection of alleles carried by all the members of a population” is the gene pool.
c.
To determine:
The phrase that describes “fitness cost” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Fitness cost in terms of genetics is related to the selective advantage provided to a geneotype in one condition, but it may be disadvantageous in other conditions.
Answer to Problem 1P
Correct answer:
Fitness cost: The advantage of a particular genotype in one situation is a disadvantage in another situation
Explanation of Solution
Fitness cost is defined as the process by which the advantage of a genotype in one condition turns out to be a disadvantage in another situation. For example, “RR” is the genotype that codes for insecticide resistance. The frequency of this genotype increases in the presence of an insecticide while its frequency reduces in the absence of an insecticide.
Thus, the term that describes “the advantage of a particular genotype in one situation is a disadvantage in another situation” is fitness cost.
d.
To determine:
The phrase that describes “allele frequencies” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Allele frequencies can be associated with gene frequencies and can be used to calculate genotype frequencies with the help of Hardy-Weinberg equilibrium.
Answer to Problem 1P
Correct answer:
Allele frequencies: p and q
Explanation of Solution
The proportion of gene copies that are of a common allele type in a population is termed as allele frequency. Geoffrey H. Hardy was a scientist who proposed the concept of Hardy-Weinberg equilibrium. This concept is used to associate the allele frequency with the genotype frequency.
According to Hardy-Weinberg equilibrium:
where:
p and q are the allele frequencies.
Thus, the p and q are allele frequencies.
e.
To determine:
The phrase that describes “heterozygote advantage” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Heterozygote advantage is related to the fitness level of heterozygous genotype.
Answer to Problem 1P
Correct answer:
Heterozygote advantage: The genotype with the highest fitness is the heterozygote
Explanation of Solution
There are two types of organisms. These are heterozygotes and homozygotes. The organism that has the same type of alleles for a particular genotype is termed as a homozygote. However, the organism that contains different alleles for genotypes is termed as heterozygotes. This type of organism produces different types of offsprings. Heterozygote advantage is used to indicate that the genotype that has the highest fitness is a heterozygote and not a homozygote.
Thus, the term that describes that a hetrozygote has the highest fitness is hetrozygote advantage.
f.
To determine:
The phrase that describes “equilibrium frequencies” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Equilibrium frequency refers to the frequency at which Δq is found to be zero.
Answer to Problem 1P
Correct answer:
Equilibrium frequency: Frequency of an allele at which Δq = 0
Explanation of Solution
The allele frequency is represented as “p and q”. Equilibrium frequency is defined as the allele frequency when Δq = 0. This is because the frequency of an allele is at equilibrium when q is equal to 0.
Thus, the equilibrium frequency is the frequency on allele when Δq = 0.
g.
To determine:
The phrase that describes “genetic drift” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Genetic drift refers to random changes of a frequency of an allele over a period of time in a population.
Answer to Problem 1P
Correct answer:
Genetic dift: Chance fluctuations in allele frequency
Explanation of Solution
The proportion of gene copies that are of a common allele type in a population is termed as allele frequency. Genetic drift is defined as the random changes in the allele frequency. The changes that are responsible for genetic drift are results of random inheritance. Thus, the term that describes chance fluctuations in the allele frequency is genetic drift.
h.
To determine:
The phrase that describes “molecular clock” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
The molecular clock plays a significant role in different areas of evolutionary biology.
Answer to Problem 1P
Correct answer:
Molecular clock: Mutations accumulate at a relatively constant rate
Explanation of Solution
An organism which is closely related has a high degree of the arrangement whereas; distantly reacted species has dissimilar arrangements. The scientists use a technique called the molecular clock. The molecular clock is used to detect the time period when organisms diverged from a common ancestor.
Thus, the term that describes the accumulation of mutation at constant rate is molecular clock.
i.
To determine:
The phrase that describes “population bottleneck” among the options given below.
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Reduction in the size of population due to environmental problems and anthropogenic activities is called population bottleneck.
Answer to Problem 1P
Correct answer:
Population bottleneck: Event that drastically lowers N
Explanation of Solution
The phenomenon by which a large population perishes randomly is termed as a population bottleneck. These are the events that rapidly lower the frequency of a population (N).
Thus, the event that drastically lowers N is called population bottleneck.
j.
To determine:
The phrase that describes “hominins” among the options given below:
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans.
Introduction:
Hominin consists of Homo sapiens, Neanderthals, and Denisovans.
Answer to Problem 1P
Correct answer:
Hominins: Homo sapiens, Neanderthals, and Denisovans.
Explanation of Solution
Hominin is a taxonomic tribe that is composed of Homo sapiens, Neanderthals, and Denisovans. It has been observed that the modern human of Europe mate with the hominins.
Thus, the term that describes “Homo sapiens, Neanderthals, and Denisovans” is hominins.
k.
The phrase that describes “fixation” among the options given below:
1. the genotype with the highest fitness is the heterozygote
2. chance fluctuations in allele frequency
3. mutations accumulate at a relatively constant rate
4. p = 1.0
5. ability to survive and reproduce
6. p and q
7. event that drastically lowers N
8. the advantage of a particular genotype in one situation is a disadvantage in another situation
9. frequency of an allele at which Δq = 0
10. collection of alleles carried by all members of a population.
11. Homo sapiens, Neanderthals, and Denisovans
Introduction:
Fixation is achieved when the frequency of specific gene has reached 100% in a population.
Answer to Problem 1P
Correct answer:
Fixation: p = 1.0
Explanation of Solution
The scientists consider a population to be fixed when a single allele is able to survive in all the individuals. It is the state at which any change after fixation cannot take place. The allele frequency (p and q) is 1.0 when fixation occurs.
Thus, the term that describes “p = 1.0” is fixation.
Want to see more full solutions like this?
Chapter 21 Solutions
Genetics: From Genes to Genomes
- A population of birds may have red feathers or orange feathers. Red feathered birds have the genotype RR or Rr. Orange feathered birds have the genotype rr. The frequency of the RR genotype is .46 a. What is the frequency of heterozygous birds? B. What is the frequency of the R allele ? C. What is the frequency of r allele?arrow_forwardIn horses, tobiano is a white spotting pattern. The tobiano allele (T) is dominant over the non-tobiano (t) allele. In an ideal horse population exhibiting Hardy–Weinberg equilibrium, 350 horses out of 465 are non-tobiano. a. Calculate the number of homozygous dominant tobiano horses. Answer b. Calculate the number of heterozygous horses. Answer c. Calculate the number of tobiano horses in the population. Answer Express your answer rounded to the nearest whole number.arrow_forwardIn a population that is in Hardy-Weinberg equilibrium, there are two possible alleles for a certain gene, A and a. If the frequency of allele A is 0.4, what fraction of the population is heterozygous? O A. 0.40 B. 0.60 C. 0.16 D. 0.48arrow_forward
- Assume you have a population with alleles A and a at a genetic locus. You measured the population and found 30 AA homozygotes, 100 Aa heterozygotes, and 70 aa homozygotes. What is the frequency of A and a in the population? a. A = 0.3; a = 0.7 b. A = 0.7; a = 0.3 c. A = 0.4; a = 0.6 d. A = 0.6; a = 0.4arrow_forward10,000 individuals are sampled from a population and are found to display one of three blood types: AA with 6800 individuals, AB with 2800 individuals and type BB with 400 individuals. a) What is the frequency of each genotype in the population? b) What is the frequency of the A allele? c) What is the frequency of the B allele? d) If the next generation contains 25,000 individuals, how many would have blood type BB, assuming the population is in Hardy-Weinberg Equilibrium?arrow_forwardWhich statement best summarizes why genetic drift tends to impact small populations more than large populations? A. Small populations have a heterozygote advantage because heterozygotes are more common than homozygotes. B. Small populations have a smaller gene pool, so random changes influence them more. C. Small populations have a relatively large gene pool, so the founder effect stabilizes their alleles.D. Small populations tend to experience directional selection, making one phenotype more common.arrow_forward
- A 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_forwardA laboratory in British Columbia, the Kelatavicla lab, starts a mouse population where the frequency of the R allele is 0.5. You maintain this population for many years under the conditions found in column A. Given the information in the table (column A) and the information above it, predict what you think will happen to the frequency of the R allele. A) The frequency of the R allele will remain stable. B) The frequency of the R allele will increase. C) The frequency of the R allele will decrease.arrow_forwardYou observe some bark beetles with different feeding behaviors. You find that the behavioral phenotypes you observed are closely associated with the following genotypes. genotype phenotype number observed BB feeds under bark 60 Bb feeds on top of bark 24 bb feeds on leaves 16 a) What are the allele frequencies and the expected number (out of 100 beetles) of genotypes? b) Calculate the Chi-Squared value (c2). Then look up the p-value using this Chi-squared calculator: https://www.mathsisfun.com/data//chi-square-calculator.html Enter “1” for Degrees of Freedom. (There are 3 genotype categories, but only 1 DF because they are not fully independent—calculated from just 2 allele frequencies). The p-value is the probability that you would see the deviance you observed by chance, assuming the null hypothesis is true). Report both values. Is the population in H-W equilibrium? c) If you answered “No” to b): Provide at least three biologically…arrow_forward
- Sickle cell anemia is maintained in human populations because individuals with a single copy of the sickle cell allele have resistance to malaria but lack the health problems of individuals with two copies of the allele. Variation at the sickle cell locus is maintained by which of the following? Group of answer choices A. heterozygote advantage B. random change in allele frequency C. mutation selection balance D. frequency dependent selectionarrow_forwardYou observe some bark beetles with different feeding behaviors. You find that the behavioral phenotypes you observed are closely associated with the following genotypes. genotype phenotype number observed BB feeds under bark 60 Bb feeds on top of bark 24 bb feeds on leaves 16 a) What are the allele frequencies and the expected number (out of 100 beetles) of genotypes? b) Calculate the Chi-Squared value (c2). Then look up the p-value only using this Chi-squared calculator: https://www.mathsisfun.com/data//chi-square-calculator.html Clear all the values in the box at upper right, enter the Chi Square value that you obtain FROM YOUR CALCULATIONS in the Chi-Square box, and enter 1 for the degrees of freedom. Is the population in H-W equilibrium? c) If you answered “No” to b): Provide at least three biologically valid reasons why the observed beetle population may not be in equilibrium. If you answered “Yes” to b): Why do you think this…arrow_forwardIn a population of 1000 baby kitties, 40 are white because of a recessive allele (b). Non-white cats are either homozygous dominant (BB) or heterozygous dominant (Bb). What is the expected frequency of heterozygous kitties in the population? Group of answer choices a) 0.16 b) 0.32 c) 0.20 d) 0.80arrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningHuman Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning