Help with Hardy-Weinberg - GRE
Card 0 of 48
A population of insects exists in which black coloration is dominant to white. If there are 64 black insects and 36 white insects in the population, what is the recessive allele frequency?
A population of insects exists in which black coloration is dominant to white. If there are 64 black insects and 36 white insects in the population, what is the recessive allele frequency?
We can use the white insect population to figure out our recessive allele frequency if we use the Hardy-Weinberg equations:
From this equation we know that 
is actually the frequency of our homozygous recessive genotype. We can determine the value of this genotypic frequency based on the information in the question. Any white insects must be homozygous recessive.
Solve for the recessive allele frequency.
We can use the white insect population to figure out our recessive allele frequency if we use the Hardy-Weinberg equations:
From this equation we know that
Solve for the recessive allele frequency.
Compare your answer with the correct one above
A population of lizards is shown to have 36 members that are homozygous dominant, 48 members that are heterozygous, and 16 members that are homozygous recessive for a particular trait. The population displays Hardy-Weinberg equilibrium. What are the allele frequencies present in this population?
A population of lizards is shown to have 36 members that are homozygous dominant, 48 members that are heterozygous, and 16 members that are homozygous recessive for a particular trait. The population displays Hardy-Weinberg equilibrium. What are the allele frequencies present in this population?
To solve this question, we must use the Hardy-Weinberg equations:
There are two ways to solve this problem. The easier way is to use the second Hardy-Weinberg equation. We are told that the population is in Hardy-Weinberg equilibrium, so the observed genotype frequencies equal the expected genotype frequencies. Each term in the second Hardy-Weinberg equation can be used in coordination with the given phenotypic frequencies.
The dominant allele frequency is 0.6 and the recessive allele frequency is 0.4.
The second method involves using our population and the total number of alleles. Since our population totals to 100, we have a total of 200 alleles (two alleles per member in the population. Next, to get the frequencies we simply have to divide the total number of a single allele by the total number of alleles in the population. For the dominant allele frequency it would look like this:
We can then get the recessive allele frequency from the first Hardy-Weinberg equation:
Both methods result in the same answer.
To solve this question, we must use the Hardy-Weinberg equations:
There are two ways to solve this problem. The easier way is to use the second Hardy-Weinberg equation. We are told that the population is in Hardy-Weinberg equilibrium, so the observed genotype frequencies equal the expected genotype frequencies. Each term in the second Hardy-Weinberg equation can be used in coordination with the given phenotypic frequencies.
The dominant allele frequency is 0.6 and the recessive allele frequency is 0.4.
The second method involves using our population and the total number of alleles. Since our population totals to 100, we have a total of 200 alleles (two alleles per member in the population. Next, to get the frequencies we simply have to divide the total number of a single allele by the total number of alleles in the population. For the dominant allele frequency it would look like this:
We can then get the recessive allele frequency from the first Hardy-Weinberg equation:
Both methods result in the same answer.
Compare your answer with the correct one above
A population of beetles exists in which black coloration is dominant to white. The allele frequencies of the population were originally o.4 for the dominant allele and 0.6 for the recessive allele. A predator was introduced that selectively ate the white beetles. The new population consists of 36 homozygous dominant black beetles, 48 heterozygous beetles, and 16 white beetles. What are the new allele frequencies?
A population of beetles exists in which black coloration is dominant to white. The allele frequencies of the population were originally o.4 for the dominant allele and 0.6 for the recessive allele. A predator was introduced that selectively ate the white beetles. The new population consists of 36 homozygous dominant black beetles, 48 heterozygous beetles, and 16 white beetles. What are the new allele frequencies?
The original allele frequencies are actually superfluous information that we will not need to use in our calculation. We are given the populations of each genotype, so we can use the Hardy-Weinberg equations to solve for the allele frequencies.
In the second equation, 
gives the frequency of the homozygous dominant phenotype and 
gives the frequency of the homozygous recessive phenotype. Using the population ratios from the question we can solve for these values to find the allele frequencies.
The problem could also be solved by summing the total number of alleles, and dividing the total of each individual allele by this number. Keep in mind that each individual carries two alleles.
The original allele frequencies are actually superfluous information that we will not need to use in our calculation. We are given the populations of each genotype, so we can use the Hardy-Weinberg equations to solve for the allele frequencies.
In the second equation,
The problem could also be solved by summing the total number of alleles, and dividing the total of each individual allele by this number. Keep in mind that each individual carries two alleles.
Compare your answer with the correct one above
Which of the following choices are likely to change the allele frequencies of the indicated populations?
I. A geographic barrier isolating a small subset of a larger population
II. The introduction of a predator that only preys upon the homozygous dominant members of the population
III. A population that displays completely random mating
Which of the following choices are likely to change the allele frequencies of the indicated populations?
I. A geographic barrier isolating a small subset of a larger population
II. The introduction of a predator that only preys upon the homozygous dominant members of the population
III. A population that displays completely random mating
Allele frequencies are the measure of an allele in relation to the total number of alleles in the given population. Introducing a predator that only preys upon homozygous dominant members will cause the number of dominant alleles to drop significantly and will, therefore, change allele frequencies. This would be an example of the bottleneck effect. Isolating a small subset of a population is going to change allele frequencies because that small subset is not likely to accurately represent the original population. This is an example of the founder effect.
Random mating is actually a factor that helps maintain allele frequencies, and is a requirement for Hardy-Weinberg equilibrium.
Allele frequencies are the measure of an allele in relation to the total number of alleles in the given population. Introducing a predator that only preys upon homozygous dominant members will cause the number of dominant alleles to drop significantly and will, therefore, change allele frequencies. This would be an example of the bottleneck effect. Isolating a small subset of a population is going to change allele frequencies because that small subset is not likely to accurately represent the original population. This is an example of the founder effect.
Random mating is actually a factor that helps maintain allele frequencies, and is a requirement for Hardy-Weinberg equilibrium.
Compare your answer with the correct one above
Which of the following is not a condition for Hardy-Weinberg equilibrium?
Which of the following is not a condition for Hardy-Weinberg equilibrium?
Of the choices, the only one that is not a Hardy-Weinberg assumption is that natural selection is occurring on the population. In fact, the exact opposite is a Hardy-Weinberg assumption. If natural selection is occurring on a population, over a large period of time, it is likely to have an effect on allele frequencies within the population.
All other answers are requirements in order for Hardy-Weinberg equilibrium to be in effect: large population size, random mating, and negligible mutation frequencies.
Of the choices, the only one that is not a Hardy-Weinberg assumption is that natural selection is occurring on the population. In fact, the exact opposite is a Hardy-Weinberg assumption. If natural selection is occurring on a population, over a large period of time, it is likely to have an effect on allele frequencies within the population.
All other answers are requirements in order for Hardy-Weinberg equilibrium to be in effect: large population size, random mating, and negligible mutation frequencies.
Compare your answer with the correct one above
Which of the following conditions are not necessary for a population to be in Hardy-Weinberg equilibrium?
Which of the following conditions are not necessary for a population to be in Hardy-Weinberg equilibrium?
The Hardy-Weinberg equilibrium states that the frequency of alleles at a locus remains constant from generation to generation. In order for this to be the case, natural selection cannot affect the alleles under consideration. All other answer choices describe conditions that do need to be met for Hardy-Weinberg equilibrium to be displayed. Note that the conditions for Hardy-Weinberg equilibrium are not met in nature.
The Hardy-Weinberg equilibrium states that the frequency of alleles at a locus remains constant from generation to generation. In order for this to be the case, natural selection cannot affect the alleles under consideration. All other answer choices describe conditions that do need to be met for Hardy-Weinberg equilibrium to be displayed. Note that the conditions for Hardy-Weinberg equilibrium are not met in nature.
Compare your answer with the correct one above
An isolated population consists of 10 males and 10 females. Two individuals are carriers of the recessive blue eye allele. Assuming all Hardy-Weinberg conditions are met. What is the frequency of the blue eye phenotype in the population?
An isolated population consists of 10 males and 10 females. Two individuals are carriers of the recessive blue eye allele. Assuming all Hardy-Weinberg conditions are met. What is the frequency of the blue eye phenotype in the population?
Use the two Hardy-Weinberg equations:
Above, 
is the frequency of the dominant allele, and 
is the frequency of the recessive allele in the isolated population.
Since there are 20 people in total on the island, that means that there are 40 alleles for eye color. 2 of the 40 are for the blue allele:
We are looking for the blue eye phenotype, which can only result from two recessive alleles.
Use the two Hardy-Weinberg equations:
Above,
Since there are 20 people in total on the island, that means that there are 40 alleles for eye color. 2 of the 40 are for the blue allele:
We are looking for the blue eye phenotype, which can only result from two recessive alleles.
Compare your answer with the correct one above
Within his rat population, a scientist is trying to generate twice as many recessive homozygotes as heterozygotes. What allelic frequency would accomplish this?
Within his rat population, a scientist is trying to generate twice as many recessive homozygotes as heterozygotes. What allelic frequency would accomplish this?
Use the Hardy-Weinberg equations:
The equation he will need to set up is the following:
Solve for 
and substitute the first equation into the equation above.
Simplify.
Lastly, find 
.
Use the Hardy-Weinberg equations:
The equation he will need to set up is the following:
Solve for
Simplify.
Lastly, find
Compare your answer with the correct one above
Assuming Hardy-Weinberg equilibrium conditions, what are the heterozygote (Bb) and homozygote recessive (bb) genotypes for a gene if the homozygote dominant (BB) genotype is 0.45?
Assuming Hardy-Weinberg equilibrium conditions, what are the heterozygote (Bb) and homozygote recessive (bb) genotypes for a gene if the homozygote dominant (BB) genotype is 0.45?
The correct answer is Bb = 0.44 and bb = 0.11.
Since we know BB = 0.45 and the equations for allele frequencies when Hardy-Weinberg equilibrium conditions are met:
and
We solve for B first:
Now we can solve for the homozygote recessive.
Lastly, solve for the heterozygote.
The correct answer is Bb = 0.44 and bb = 0.11.
Since we know BB = 0.45 and the equations for allele frequencies when Hardy-Weinberg equilibrium conditions are met:
and
We solve for B first:
Now we can solve for the homozygote recessive.
Lastly, solve for the heterozygote.
Compare your answer with the correct one above
Which of the following is not an assumption of the Hardy-Weinberg equilibrium?
Which of the following is not an assumption of the Hardy-Weinberg equilibrium?
Non-random mating is not an assumption of the Hardy-Weinberg equilibrium, in fact, in order to make predictions about the next generation, random mating must be assumed. Additionally, no new mutations, no gene flow, no genetic drift, and no natural selection must also occur. If any of these phenomenon are present in a population, we can not estimate allele frequencies in subsequent generations due to chance, rather selective pressures may favor one allele over another allele.
Non-random mating is not an assumption of the Hardy-Weinberg equilibrium, in fact, in order to make predictions about the next generation, random mating must be assumed. Additionally, no new mutations, no gene flow, no genetic drift, and no natural selection must also occur. If any of these phenomenon are present in a population, we can not estimate allele frequencies in subsequent generations due to chance, rather selective pressures may favor one allele over another allele.
Compare your answer with the correct one above
What are the phenotypic ratios for a given population for which the proportion of the dominant allele is 0.55 and that of the recessive allele is 0.45?
What are the phenotypic ratios for a given population for which the proportion of the dominant allele is 0.55 and that of the recessive allele is 0.45?
To solve this problem, assume Hardy-Weinberg equilibrium and use the associated equations to solve:
is dominant allele and 
is recessive allele
To find the phenotype ratios:
homozygous dominant
heterozygous
homozygous recessive
To solve this problem, assume Hardy-Weinberg equilibrium and use the associated equations to solve:
To find the phenotype ratios:
Compare your answer with the correct one above
Which of the following is not a tenet of Hardy-Weinberg equilibrium?
Which of the following is not a tenet of Hardy-Weinberg equilibrium?
The Hardy-Weinberg equilibrium does not account for genetic drift. The Hardy-Weinberg law states that genetic frequencies will remain constant in a population from generation to generation in the absence of evolutionary influences. Therefore, there is no migration, natural selection, nonrandom mating, or small populations in a Hardy-Weinberg population.
The Hardy-Weinberg equilibrium does not account for genetic drift. The Hardy-Weinberg law states that genetic frequencies will remain constant in a population from generation to generation in the absence of evolutionary influences. Therefore, there is no migration, natural selection, nonrandom mating, or small populations in a Hardy-Weinberg population.
Compare your answer with the correct one above
A population of insects exists in which black coloration is dominant to white. If there are 64 black insects and 36 white insects in the population, what is the recessive allele frequency?
A population of insects exists in which black coloration is dominant to white. If there are 64 black insects and 36 white insects in the population, what is the recessive allele frequency?
We can use the white insect population to figure out our recessive allele frequency if we use the Hardy-Weinberg equations:
From this equation we know that is actually the frequency of our homozygous recessive genotype. We can determine the value of this genotypic frequency based on the information in the question. Any white insects must be homozygous recessive.
Solve for the recessive allele frequency.
We can use the white insect population to figure out our recessive allele frequency if we use the Hardy-Weinberg equations:
From this equation we know that
Solve for the recessive allele frequency.
Compare your answer with the correct one above
A population of lizards is shown to have 36 members that are homozygous dominant, 48 members that are heterozygous, and 16 members that are homozygous recessive for a particular trait. The population displays Hardy-Weinberg equilibrium. What are the allele frequencies present in this population?
A population of lizards is shown to have 36 members that are homozygous dominant, 48 members that are heterozygous, and 16 members that are homozygous recessive for a particular trait. The population displays Hardy-Weinberg equilibrium. What are the allele frequencies present in this population?
To solve this question, we must use the Hardy-Weinberg equations:
There are two ways to solve this problem. The easier way is to use the second Hardy-Weinberg equation. We are told that the population is in Hardy-Weinberg equilibrium, so the observed genotype frequencies equal the expected genotype frequencies. Each term in the second Hardy-Weinberg equation can be used in coordination with the given phenotypic frequencies.
The dominant allele frequency is 0.6 and the recessive allele frequency is 0.4.
The second method involves using our population and the total number of alleles. Since our population totals to 100, we have a total of 200 alleles (two alleles per member in the population. Next, to get the frequencies we simply have to divide the total number of a single allele by the total number of alleles in the population. For the dominant allele frequency it would look like this:
We can then get the recessive allele frequency from the first Hardy-Weinberg equation:
Both methods result in the same answer.
To solve this question, we must use the Hardy-Weinberg equations:
There are two ways to solve this problem. The easier way is to use the second Hardy-Weinberg equation. We are told that the population is in Hardy-Weinberg equilibrium, so the observed genotype frequencies equal the expected genotype frequencies. Each term in the second Hardy-Weinberg equation can be used in coordination with the given phenotypic frequencies.
The dominant allele frequency is 0.6 and the recessive allele frequency is 0.4.
The second method involves using our population and the total number of alleles. Since our population totals to 100, we have a total of 200 alleles (two alleles per member in the population. Next, to get the frequencies we simply have to divide the total number of a single allele by the total number of alleles in the population. For the dominant allele frequency it would look like this:
We can then get the recessive allele frequency from the first Hardy-Weinberg equation:
Both methods result in the same answer.
Compare your answer with the correct one above
A population of beetles exists in which black coloration is dominant to white. The allele frequencies of the population were originally o.4 for the dominant allele and 0.6 for the recessive allele. A predator was introduced that selectively ate the white beetles. The new population consists of 36 homozygous dominant black beetles, 48 heterozygous beetles, and 16 white beetles. What are the new allele frequencies?
A population of beetles exists in which black coloration is dominant to white. The allele frequencies of the population were originally o.4 for the dominant allele and 0.6 for the recessive allele. A predator was introduced that selectively ate the white beetles. The new population consists of 36 homozygous dominant black beetles, 48 heterozygous beetles, and 16 white beetles. What are the new allele frequencies?
The original allele frequencies are actually superfluous information that we will not need to use in our calculation. We are given the populations of each genotype, so we can use the Hardy-Weinberg equations to solve for the allele frequencies.
In the second equation, gives the frequency of the homozygous dominant phenotype and gives the frequency of the homozygous recessive phenotype. Using the population ratios from the question we can solve for these values to find the allele frequencies.
The problem could also be solved by summing the total number of alleles, and dividing the total of each individual allele by this number. Keep in mind that each individual carries two alleles.
The original allele frequencies are actually superfluous information that we will not need to use in our calculation. We are given the populations of each genotype, so we can use the Hardy-Weinberg equations to solve for the allele frequencies.
In the second equation,
The problem could also be solved by summing the total number of alleles, and dividing the total of each individual allele by this number. Keep in mind that each individual carries two alleles.
Compare your answer with the correct one above
Which of the following choices are likely to change the allele frequencies of the indicated populations?
I. A geographic barrier isolating a small subset of a larger population
II. The introduction of a predator that only preys upon the homozygous dominant members of the population
III. A population that displays completely random mating
Which of the following choices are likely to change the allele frequencies of the indicated populations?
I. A geographic barrier isolating a small subset of a larger population
II. The introduction of a predator that only preys upon the homozygous dominant members of the population
III. A population that displays completely random mating
Allele frequencies are the measure of an allele in relation to the total number of alleles in the given population. Introducing a predator that only preys upon homozygous dominant members will cause the number of dominant alleles to drop significantly and will, therefore, change allele frequencies. This would be an example of the bottleneck effect. Isolating a small subset of a population is going to change allele frequencies because that small subset is not likely to accurately represent the original population. This is an example of the founder effect.
Random mating is actually a factor that helps maintain allele frequencies, and is a requirement for Hardy-Weinberg equilibrium.
Allele frequencies are the measure of an allele in relation to the total number of alleles in the given population. Introducing a predator that only preys upon homozygous dominant members will cause the number of dominant alleles to drop significantly and will, therefore, change allele frequencies. This would be an example of the bottleneck effect. Isolating a small subset of a population is going to change allele frequencies because that small subset is not likely to accurately represent the original population. This is an example of the founder effect.
Random mating is actually a factor that helps maintain allele frequencies, and is a requirement for Hardy-Weinberg equilibrium.
Compare your answer with the correct one above
Which of the following is not a condition for Hardy-Weinberg equilibrium?
Which of the following is not a condition for Hardy-Weinberg equilibrium?
Of the choices, the only one that is not a Hardy-Weinberg assumption is that natural selection is occurring on the population. In fact, the exact opposite is a Hardy-Weinberg assumption. If natural selection is occurring on a population, over a large period of time, it is likely to have an effect on allele frequencies within the population.
All other answers are requirements in order for Hardy-Weinberg equilibrium to be in effect: large population size, random mating, and negligible mutation frequencies.
Of the choices, the only one that is not a Hardy-Weinberg assumption is that natural selection is occurring on the population. In fact, the exact opposite is a Hardy-Weinberg assumption. If natural selection is occurring on a population, over a large period of time, it is likely to have an effect on allele frequencies within the population.
All other answers are requirements in order for Hardy-Weinberg equilibrium to be in effect: large population size, random mating, and negligible mutation frequencies.
Compare your answer with the correct one above
Which of the following conditions are not necessary for a population to be in Hardy-Weinberg equilibrium?
Which of the following conditions are not necessary for a population to be in Hardy-Weinberg equilibrium?
The Hardy-Weinberg equilibrium states that the frequency of alleles at a locus remains constant from generation to generation. In order for this to be the case, natural selection cannot affect the alleles under consideration. All other answer choices describe conditions that do need to be met for Hardy-Weinberg equilibrium to be displayed. Note that the conditions for Hardy-Weinberg equilibrium are not met in nature.
The Hardy-Weinberg equilibrium states that the frequency of alleles at a locus remains constant from generation to generation. In order for this to be the case, natural selection cannot affect the alleles under consideration. All other answer choices describe conditions that do need to be met for Hardy-Weinberg equilibrium to be displayed. Note that the conditions for Hardy-Weinberg equilibrium are not met in nature.
Compare your answer with the correct one above
An isolated population consists of 10 males and 10 females. Two individuals are carriers of the recessive blue eye allele. Assuming all Hardy-Weinberg conditions are met. What is the frequency of the blue eye phenotype in the population?
An isolated population consists of 10 males and 10 females. Two individuals are carriers of the recessive blue eye allele. Assuming all Hardy-Weinberg conditions are met. What is the frequency of the blue eye phenotype in the population?
Use the two Hardy-Weinberg equations:
Above, is the frequency of the dominant allele, and is the frequency of the recessive allele in the isolated population.
Since there are 20 people in total on the island, that means that there are 40 alleles for eye color. 2 of the 40 are for the blue allele:
We are looking for the blue eye phenotype, which can only result from two recessive alleles.
Use the two Hardy-Weinberg equations:
Above,
Since there are 20 people in total on the island, that means that there are 40 alleles for eye color. 2 of the 40 are for the blue allele:
We are looking for the blue eye phenotype, which can only result from two recessive alleles.
Compare your answer with the correct one above
Within his rat population, a scientist is trying to generate twice as many recessive homozygotes as heterozygotes. What allelic frequency would accomplish this?
Within his rat population, a scientist is trying to generate twice as many recessive homozygotes as heterozygotes. What allelic frequency would accomplish this?
Use the Hardy-Weinberg equations:
The equation he will need to set up is the following:
Solve for and substitute the first equation into the equation above.
Simplify.
Lastly, find .
Use the Hardy-Weinberg equations:
The equation he will need to set up is the following:
Solve for
Simplify.
Lastly, find
Compare your answer with the correct one above