Question 1

Which aspect of population genetics can lead to changes in allele frequencies in a new mixed population following migration?

Accepted Answer

Gene flow, which is the movement of genes between different populations, can lead to changes in allele frequencies in a new mixed population following migration. This occurs as migrant individuals bring their unique genetic makeup into the new population, which can alter the frequencies of certain alleles. Natural selection, mutation, founder effect, and bottleneck effect are also important factors in population genetics, but they do not necessarily lead to changes in allele frequencies through migration alone.

Question 2

Which aspect of population genetics refers to chance fluctuations of allele frequencies resulting from sampling error and is more prominent in small, isolated populations?

Accepted Answer

Gene drift refers to the chance fluctuations of allele frequencies resulting from sampling error and is more prominent in small, isolated populations. The founder effect and bottleneck effect are specific types of gene drift that occur when a small group of individuals becomes isolated from the larger population or when the population size is drastically reduced, respectively. Mutation and gene flow refer to other aspects of population genetics.

Question 3

The coefficient of inbreeding (F)can be used to estimate the proportion of loci that are __________.

Accepted Answer

The coefficient of inbreeding (F) is a measure of the probability that two alleles at any given locus in an individual are identical by descent. Therefore, a higher F value indicates a higher proportion of loci that are homozygous identical by descent.

Question 4

Phenylketonuria (PKU)is extremely common in Ireland, affecting approximately 1 in 4500 live births. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of PKU carriers?

Accepted Answer

In Hardy-Weinberg equilibrium, the frequency of homozygous recessive individuals (affected by PKU) can be calculated using the equation: q^2 = 1/4500, where q is the frequency of the recessive allele. 
Solving for q: 
q^2 = 1/4500 
q = sqrt(1/4500) 
q = 0.0219 
The frequency of carriers (heterozygotes) can be calculated using the equation: 2pq, where p is the frequency of the dominant allele and q is the frequency of the recessive allele. 
p + q = 1 
p = 1 - q 
p = 1 - 0.0219 
p = 0.9781 
2pq = 2(0.9781)(0.0219) 
2pq = 0.0428 or 4.28% 
Therefore, the frequency of PKU carriers is approximately 2.9%.

Question 5

All Old Order Amish families from Lancaster County with Ellis-van Creveld syndrome can trace their genealogies to Mr. and Mrs. Samuel King, who immigrated to Lancaster County in 1744. This is an example of __________.

Accepted Answer

This is an example of founder effect, which occurs when a small group of individuals establishes a new population, and their limited gene pool leads to increased frequency of certain alleles or disorders. In this case, all individuals with Ellis-van Creveld syndrome can trace their genealogy to a single couple who immigrated to Lancaster County in 1744.

Question 6

Which of the following is an example of a postzygotic mechanism for reproductive isolation?

Accepted Answer

Hybrid sterility is a postzygotic mechanism of reproductive isolation in which the hybrid offspring of two different species are unable to produce viable or fertile offspring of their own. This occurs because the genetic differences between the two species make it difficult for the chromosomes of the hybrid to properly pair and segregate during meiosis, resulting in abnormal gametes and infertility.

Question 7

If an X-linked recessive trait has a frequency of 5% in males, what percentage of females are carriers? (Assume that the population is in Hardy-Weinberg equilibrium.)

Accepted Answer

The frequency of the recessive allele in males is 0.05, so the frequency of the dominant allele is 0.95. The frequency of heterozygous females is 2pq, where p is the frequency of the dominant allele and q is the frequency of the recessive allele. Therefore, the frequency of heterozygous females is 2(0.95)(0.05) = 0.095, or 9.5%.

Question 8

What type of statistical analysis is used to compare observed and expected results in order to evaluate the validity of an estimate based on the Hardy-Weinberg equilibrium?

Accepted Answer

The answer of What type of statistical analysis is used...

Question 9

Given the following pedigree, what is the coefficient of inbreeding for individual IV-1?

Accepted Answer

The answer of Given the following pedigree, what is the...

Question 10

Physical separation of a segment of a large population by a physical barrier that prevents gene flow can lead to __________.

Accepted Answer

The physical barrier preventing gene flow would result in the formation of two separate populations that are no longer able to interbreed. Over time, genetic differences may accumulate in these separate populations, leading to the development of new species through allopatric speciation.

Question 11

You want to calculate the frequency of the allele causing sickle cell disease in your patients, and you know the genotypes of every individual. Assuming the population is not in Hardy-Weinberg equilibrium due to population substructure, which method can be used to calculate allele frequency?

Accepted Answer

The answer of You want to calculate the frequency of...

Question 12

In a group of 500 people, the frequency of genotype NN is 40%. Assuming both autosomal inheritance and that the population is in Hardy-Weinberg equilibrium, how many individuals would you expect to have the MN genotype?

Accepted Answer

The frequency of the N allele is sqrt(0.4) = 0.632. The frequency of the M allele is 1 - 0.632 = 0.368. The frequency of the MN genotype is 2 * 0.632 * 0.368 = 0.464. The number of individuals with the MN genotype is 0.464 * 500 = 232.

Question 13

Cheetahs exhibit significant inbreeding and loss of heterozygosity due to overhunting and loss of habitat experienced at some point in their evolutionary history. Which genetic mechanism occurs when a large population is substantially reduced at random, acting independently of natural selection?

Accepted Answer

The explanation includes the reduction of a large population at random, which is the key characteristic of a bottleneck effect. The other options are not relevant to the given information.

Question 14

Given the following genetic profile, what is the mean fitness of the population? Genotype A₁A₁ A₁A₂ A₂A₂ Frequency 0.55 0.20 0.25 Number 2750 1000 1250 Relative fitness (w)1.0 0.75 0.50

Accepted Answer

The mean fitness of the population is calculated by multiplying the frequency of each genotype by its relative fitness and summing these products: (0.55 * 1.0) + (0.20 * 0.75) + (0.25 * 0.50) = 0.825.

Question 15

Mexican hairless dogs are heterozygous (Hh), carrying a single copy of the recessive lethal allele. In a given population, the Hh genotypic frequency is 60% and the frequency of each homozygote
Is 20%. Assuming w = 1 for the Hh and hh dogs, what is the estimated genotypic frequency of the lethal HH genotype after reproduction?

Accepted Answer

The answer of Mexican hairless dogs are heterozygous (Hh), carrying...

Question 16

In CODIS, what type of genetic marker is used to predict population genotype frequencies?

Accepted Answer

STRPs (short tandem repeat polymorphisms) are the genetic markers used in CODIS to predict population genotype frequencies. These markers consist of repeating stretches of 2-6 base pairs within the DNA sequence that vary in length and number of repeats between individuals, making them useful in identifying genetic differences between populations.

Question 17

When populations share a single habitat but are isolated by genetic or postzygotic mechanisms that prevent gene flow, what process can cause populations to diverge?

Accepted Answer

When populations share a single habitat but are isolated by genetic or postzygotic mechanisms that prevent gene flow, sympatric speciation can cause populations to diverge. In this process, a new species can arise from a single ancestral species without geographical isolation. This can occur due to various mechanisms such as polyploidy, habitat differentiation, and sexual selection. Random mating (A) and random mutation (D) may lead to genetic variation within populations but do not necessarily cause divergence between populations. Allopatric speciation (B) occurs when populations are separated geographically, so it is not applicable to the scenario given in the question. Gene duplication (E) can provide a new genetic material for evolution but alone does not cause speciation.

Question 18

In the same population of patients you examined for sickle cell allele frequencies, you now want to test whether the disease symptoms are related to blood type. Since blood type is a codominant trait and the alleles are easily identifiable by the phenotype (blood type)of the individuals, which method is most helpful for identifying blood type allele frequency?

Accepted Answer

The blood type alleles are easily identifiable by the phenotype of the individuals, making the allele-counting method the most appropriate for identifying blood type allele frequency. This method involves counting the number of individuals with each blood type to determine the frequency of each allele in the population.

Question 19

Both the founder effect and the bottleneck effect are mechanisms that produce large allele frequency sampling errors in a small population due to __________.

Accepted Answer

Both the founder effect and the bottleneck effect are examples of genetic drift, which involves random changes in allele frequencies in small populations.

Question 20

The process by which an original species is transformed into a new species over an extended period of time that spans many generations is known as __________.

Accepted Answer

Anagenesis is the process by which a single species evolves into a new species over time without branching into multiple lineages.

Quiz 22: Population Genetics and Evolution

Which aspect of population genetics can lead to changes in allele frequencies in a new mixed population following migration?

Which aspect of population genetics refers to chance fluctuations of allele frequencies resulting from sampling error and is more prominent in small, isolated populations?

The coefficient of inbreeding (F) can be used to estimate the proportion of loci that are __________.

Phenylketonuria (PKU) is extremely common in Ireland, affecting approximately 1 in 4500 live births. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of PKU carriers?

All Old Order Amish families from Lancaster County with Ellis-van Creveld syndrome can trace their genealogies to Mr. and Mrs. Samuel King, who immigrated to Lancaster County in 1744. This is an example of __________.

Which of the following is an example of a postzygotic mechanism for reproductive isolation?

If an X-linked recessive trait has a frequency of 5% in males, what percentage of females are carriers? (Assume that the population is in Hardy-Weinberg equilibrium.)

What type of statistical analysis is used to compare observed and expected results in order to evaluate the validity of an estimate based on the Hardy-Weinberg equilibrium?

Given the following pedigree, what is the coefficient of inbreeding for individual IV-1?

Physical separation of a segment of a large population by a physical barrier that prevents gene flow can lead to __________.

You want to calculate the frequency of the allele causing sickle cell disease in your patients, and you know the genotypes of every individual. Assuming the population is not in Hardy-Weinberg equilibrium due to population substructure, which method can be used to calculate allele frequency?

In a group of 500 people, the frequency of genotype NN is 40%. Assuming both autosomal inheritance and that the population is in Hardy-Weinberg equilibrium, how many individuals would you expect to have the MN genotype?

Cheetahs exhibit significant inbreeding and loss of heterozygosity due to overhunting and loss of habitat experienced at some point in their evolutionary history. Which genetic mechanism occurs when a large population is substantially reduced at random, acting independently of natural selection?

Given the following genetic profile, what is the mean fitness of the population? Genotype A₁A₁ A₁A₂ A₂A₂ Frequency 0.55 0.20 0.25 Number 2750 1000 1250 Relative fitness (w) 1.0 0.75 0.50

In CODIS, what type of genetic marker is used to predict population genotype frequencies?

When populations share a single habitat but are isolated by genetic or postzygotic mechanisms that prevent gene flow, what process can cause populations to diverge?

Both the founder effect and the bottleneck effect are mechanisms that produce large allele frequency sampling errors in a small population due to __________.

The process by which an original species is transformed into a new species over an extended period of time that spans many generations is known as __________.

Quiz 22: Population Genetics and Evolution

Which aspect of population genetics can lead to changes in allele frequencies in a new mixed population following migration?

Which aspect of population genetics refers to chance fluctuations of allele frequencies resulting from sampling error and is more prominent in small, isolated populations?

The coefficient of inbreeding (F) can be used to estimate the proportion of loci that are __________.

Phenylketonuria (PKU) is extremely common in Ireland, affecting approximately 1 in 4500 live births. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of PKU carriers?

All Old Order Amish families from Lancaster County with Ellis-van Creveld syndrome can trace their genealogies to Mr. and Mrs. Samuel King, who immigrated to Lancaster County in 1744. This is an example of __________.

Which of the following is an example of a postzygotic mechanism for reproductive isolation?

If an X-linked recessive trait has a frequency of 5% in males, what percentage of females are carriers? (Assume that the population is in Hardy-Weinberg equilibrium.)

What type of statistical analysis is used to compare observed and expected results in order to evaluate the validity of an estimate based on the Hardy-Weinberg equilibrium?

Given the following pedigree, what is the coefficient of inbreeding for individual IV-1?

Physical separation of a segment of a large population by a physical barrier that prevents gene flow can lead to __________.

You want to calculate the frequency of the allele causing sickle cell disease in your patients, and you know the genotypes of every individual. Assuming the population is not in Hardy-Weinberg equilibrium due to population substructure, which method can be used to calculate allele frequency?

In a group of 500 people, the frequency of genotype NN is 40%. Assuming both autosomal inheritance and that the population is in Hardy-Weinberg equilibrium, how many individuals would you expect to have the MN genotype?

Cheetahs exhibit significant inbreeding and loss of heterozygosity due to overhunting and loss of habitat experienced at some point in their evolutionary history. Which genetic mechanism occurs when a large population is substantially reduced at random, acting independently of natural selection?

Given the following genetic profile, what is the mean fitness of the population? Genotype A1A1 A1A2 A2A2 Frequency 0.55 0.20 0.25 Number 2750 1000 1250 Relative fitness (w) 1.0 0.75 0.50

In CODIS, what type of genetic marker is used to predict population genotype frequencies?

When populations share a single habitat but are isolated by genetic or postzygotic mechanisms that prevent gene flow, what process can cause populations to diverge?

Both the founder effect and the bottleneck effect are mechanisms that produce large allele frequency sampling errors in a small population due to __________.

The process by which an original species is transformed into a new species over an extended period of time that spans many generations is known as __________.

Given the following genetic profile, what is the mean fitness of the population? Genotype A₁A₁ A₁A₂ A₂A₂ Frequency 0.55 0.20 0.25 Number 2750 1000 1250 Relative fitness (w) 1.0 0.75 0.50