Evolution Exam Compilation

The equilibrium value for D for any pair of loci is....

0

What is the Frequency of a New Mutation for a population size of N = 10?

0.05

The fitness (w) of the A2A2 genotype is 0.8 (w = 0.8). What is the strength of selection (s) on the A2 allele?

0.2

N (population size) = 100 P (number of allele A1 in the population) = 50 What is p (frequency of allele A1 in the population)? N (population size) = 100P (number of allele A1 in the population) = 50What is p (frequency of allele A1 in the population)?Hint: Each individual carries two alleles.

0.25

For two coin flips, what is the probability of getting a 'heads' and a 'tails' in any order? (heads and tails) or (tails and heads) The probability of a coin flip resulting in 'heads' showing = ½ = 0.5For two coin flips, what is the probability of getting a 'heads' and a 'tails' in any order?(heads and tails) or (tails and heads)

0.5

In question 4 the dominance of the A1 allele is h1 = 0. What is the fitness (w) of the A1 A2 genotype?

0.8

There is selection against A2. If s = 0.2 what would be the fitness (w) of the A2A2 genotype?

0.8

For the A2 allele s = 0.2. What is the fitness (w) of the A1A2 genotype if h2 = 0.5?

0.9

Synapomorphic

1 1 0 0 0 0 0 1 1 1

Which traits are useful to a group taxa in the phylogeny?

1 1 0 0 0 0 0 1 1 1

In the island model of migration, with no drift or selection we expect....

1. The equilibrium allele frequency is the average of all populations

You estimate fitness (w) for all the individuals in a population. The maximum possible value for w is ...

1.0

What is the probability of getting a 'heads' with a coin flip and a 3 with a die toss? The probability of a coin flip resulting in 'heads' showing = ½ = 0.5The probability of throwing a '2' using a six-sided die = 1/6 = 0.17What is the probability of getting a 'heads' with a coin flip and a 3 with a die toss?(heads ​[coin] and 3 ​[die])Give your answer as a the denominator of the fraction: 1/?Your answer will be an integer.

12

High gametic disequilibrium in hybrid populations for alleles that are fixed in allopatric populations could indicative of...... 1. Outbreeding. 2. Large population size. 3. Recent gene flow from allopatric populations. 4. Both 1 and 2 are true. 5. Both 1 and 3 are true. 6. Both 2 and 3 are true. 7. All, 1, 2, and 3 are true.

3. Recent gene flow from allopatric populations.

Monsanto requires farmers to plant non Bt corn in addition to Bt corn. How does this prevent evolution of resistance to the Bt pesticide?

3. The effects of selection are counterbalanced by gene flow

The heterozygosity of a population immediately after a founder event (bottleneck) depends on.... 1. Heterozygosity of the source population. 2. The number of founders. 3. Population growth rate. 4. Both 1 and 2 are true. 5. Both 2 and 3 are true. 6. Both 1 and 3 are true. 7. All, 1, 2, and 3 are true.

4. Both 1 and 2 are true

Detrimental (s>0) recessive alleles (h=0) are generally maintained in populations because... 1. When the allele frequency is close to zero the majority of detrimental alleles will be in heterozygous A1A2 genotypes. 2. The detrimental allele is hidden from the effect of selection in the A1A2 genotypes. 3. Selection becomes weaker as allele frequency approaches zero. 4. Both 1 and 2 are true. 5. Both 2 and 3 are true. 6. Both 1 and 3 are true. 7. All, 1, 2, and 3 are true.

4. Both 1 and 2 are true.

In the stepping stone model of migration, with no drift or selection we expect.... 1. A pattern of isolation by distance will develop. 2. Populations that are closer to each other will have more similar allele frequencies. 3. The equilibrium allele frequency will be the same as the continent. 4. Both 1 and 2 are true. 5. Both 2 and 3 are true. 6. Both 1 and 3 are true. 7. All, 1, 2, and 3 are true.

4. Both 1 and 2 are true.

Why would we expect a mutation for asexual reproduction to be advantageous in a population of sexually reproducing individuals? 1. Asexual reproduction results in only female offspring. 2. The number of individuals in an asexual strain will increase at twice the rate. 3. There is no recombination during asexual reproduction. 4. Both 1 and 2 are true. 5. Both 1 and 3 are true. 6. Both 2 and 3 are true. 7. All 1, 2, and 3 are true.

4. Both 1 and 2 are true.

For an allele under selection the effects of inbreeding will be... 1. Inbreeding will expose more deleterious recessive alleles to the effects of selection. 2. Inbreeding will accelerate the fixation of advantageous recessive alleles. 3. Inbreeding will lead to purging of genetic load if it is primarily due to overdominance. 4. Only 1 and 2 are true. 5. Only 1 and 3 are true. 6. Only 2 and 3 are true. 7. All 1, 2, and 3 are true.

4. Only 1 and 2 are true.

What is true of the inbreeding coefficient (f)? 1. It represents the probability of having homozygous alleles that are identical by descent. 2. If f = 0 in one generation it can increase to a maximum of f = 0.5 in the next generation. 3. After one generation of mating among unrelated individuals f = 0. 4. Over successive generations of inbreeding f will asymptotically approach 1.0. 5. All of the above (1-4) are true of f. 6. None of the above (1-4) are true of f.

5. All of the above (1-4) are true of f. The probability that X receives A1 is ½ . The probability that Y receives A1 is ½ . There are 4 alleles that could be inherited gxy = 4[½(½) X ½(½)] = ¼ The probability that two alleles at a locus are ibd = (½x½ )x(½ x½) (one allele) f = 4(½x½ )x(½ x½) = 0.25 f = (1/2)n , where n = number of ancestors in the chain. f = sum of (1/2)n for multiple ancestors.

You sample several populations of the rare Fender's Blue butterfly in the Willamette Valley for microsatellite variation (a neutral marker - no selection). Your estimate of FST for differentiation among these populations is very high. This could be due to: 1. Effective population sizes (Ne) are small. 2. High rates of dispersal among populations. 3. The value of Nm is probably < 1.0 4. Both 1 and 2 are true. 5. Both 1 and 3 are true. 6. Both 2 and 3 are true. 7. All 1, 2, and 3 are true.

5. Both 1 and 3 are true Heterozygosity: Differentiation among populations (FST ) will decrease. - More differentiation when Ne is small. - More differentiation when Nm is lower

In a population subject to genetic drift you estimate allele frequency of A1 as p = 0.80 in generation one. What can you predict about the future effects of drift on the frequency of A1 and A2 in this population? 1. The A1 allele will ultimately be lost or fixed. 2. Change in allele frequency between generations is more likely to be large if the Ne is large. 3. The chance of fixation for A2 is 20%. 4. Both 1 and 2 are true. 5. Both 2 and 3 are true. 6. Both 1 and 3 are true. 7. All, 1, 2, and 3 are true.

6. Both 1 and 3 are true.

Conditions necessary to detect recent gene flow among populations using gametic disequilibrium: 1. Weak linkage 2. Gene flow must have been within the last few generations 3. Populations must differ in allele frequencies 4. Both 1 and 2 must be true 5. Both 1 and 3 must be true 6. Both 2 and 3 must be true 7. All, 1, 2, and 3 must be true

6. Both 2 and 3 must be true

The effective population size is expected to be lower than the census population size when... 1. There is an unequal sex ratio. 2. There is unequal reproductive success. 3. There is limited dispersal. 4. Only 1 and 2 are true. 5. Only 1 and 3 are true. 6. Only 2 and 3 are true. 7. All 1, 2, and 3 are true.

7. All 1, 2 and 3 are true

What generalization can we make about selection on allele frequencies in populations? 1. Rate of change in q (Δq) will depend on s 2. Rate of change in q (Δq) will slow as q approaches equilibrium. 3. Internal equilibria (q > 0 and q < 1.0) are only possible if fitness of the heterozygote is higher or lower than both homozygotes. 4. Both 1 and 2 are true. 5. Both 2 and 3 are true. 6. Both 1 and 3 are true. 7. All, 1, 2, and 3 are true.

7. All 1, 2 and 3 are true.

In 100 populations subject to genetic drift you estimate average allele frequency of A1 as p = 0.40 in generation one. What can you predict about the future effects of drift on the frequency of A1 across all of these populations? 1. The mean will increase. 2. The variance will increase. 3. The mean will stay about the same. 4. The variance will stay about the same. 5. Both 1 and 2 are true. 6. Both 3 and 4 are true. 7. Both 2 and 3 are true. 8. Both 1 and 4 are true.

7. Both 2 and 3 are true

Migration will have the effect of.... 1. Decreasing allele frequency differences among populations. 2. Counterbalancing the effects of genetic drift. 3. Counterbalancing the effects of selection. 4. Both 1 and 2 are true. 5. Both 1 and 3 are true. 6. Both 2 and 3 are true. 7. All 1, 2, and 3 are true.

7. all 1, 2 and 3 are true

Genetic drift will have the effect of.... 1. Increasing allele frequency differences among populations. 2. Counterbalancing the effects of migration. 3. Counterbalancing the effects of selection. 4. Both 1 and 2 are true. 5. Both 1 and 3 are true. 6. Both 2 and 3 are true. 7. All 1, 2, and 3 are true.

7. all 1,2 and 3 are true Mean allele frequency across all populations will remain the same The variance in allele frequency among populations will increase The proportion of alleles becoming fixed/lost across populations is equivalent to the initial allele frequency Effective population size (Ne) that is lower than census size (N) is due to: Spatial structure .Unequal sex ratio Unequal reproductive success.

What factor(s) can slow the approach to equilibrium for D?

A low recombination rate(r) Inbreeding Only A and B are true

A good example of evolution would be:

A plant doubles its genome to become tetraploid and produces fertile offspring

On a phylogenetic tree, a "node" refers to:

A point where a branch splits A hypothetical ancestor

Why is sex important in evolution? 1. It increases the variance in fitness among copies of each chromosome. 2. It may concentrate deleterious recessive alleles on some chromosomes so they can more effectively be removed by selection. 3. It may combine advantageous alleles on single chromosomes. 4. Only 1 and 2 are true. 5. Only 1 and 3 are true. 6. Only 2 and 3 are true. 7. All 1, 2, and 3 are true.

All 1,2, and 3 are true

What general statement can we make for individual populations subject only to genetic drift and not selection or migration? 1. Genetic drift ultimately leads to the loss of genetic variation. 2. Distribution of probable magnitude of change from one generation to the next depends only on the effective population size (Ne). 3. In the absence of mutation, one allele will eventually go to fixation (p = 1.0 or q = 1.0). 4. The probability of fixation is equal to the initial allele frequency (p0). 5. All of the above are true

All of the above are true The direction of change in allele frequencies from one generation to the next is unpredictable. The magnitude of change is inversely related to the size of the population. The long term effects are: 1. To reduce within population genetic variation. 2. To cause allele frequencies in different populations to diverge from each other.

A theory can be defined as:

An explanation of processes that is consistent with a large number of observations

A phylogeny represents:

An hypothesis of the historical relationships among organisms.

Which of the following is true of evolution?

B - 2.Evolution is a way to improve species- make them better adapted to their habitat.

To demonstrate natural selection on a trait, it would need to:

Be associated with a measure of fitness

You use a single gene to estimate a phylogeny for plants in the mustard family. You resample subsets of the data thousands of times to determine the support for each branch. This is referred to as

Bootstrapping

Are transitions or transversions more informative for the reconstruction of phylogenies?

C - 3.Transversions because they are less likely to produce homoplaisy.

Changes in DNA methylation patterns can

Change the phenotype of an organism in one generation In plants, can be inherited by offspring so they display the same phenotype as the parent

The rhinoceros has horns derived from hair follicles while horns in antelope are derived from bone. This is an example of:

Convergent evolution homoplaisy

Selection on corn- these studies demonstrate:

D - 4.Protein and oil content are heritable in corn.

Which of the following is more accurate?

Darwins basic ideas of evolution are still true today but our understanding of the importance processes have changed as new information has been gathered.

Inbreeding depression is primarily due to

Deleterious recessive alleles Loss of fitness due to consanguineous matings (i.e., pairs that share more alleles identical by descent than the random expectation) Expressed as the ratio of fitnesses between inbred and outbred progeny. δ = 1 - ws/wo When δ < 0.5 we expect the evolution of complete self fertilization.

You return to Forest Park the following year after measuring measuring beak width of spotted towhees the year before and find that the range of variation in beak width is narrower than it was the previous spring, but not as narrow as it had been at end of the previous summer. What have you demonstrated?

Evolution by natural selection

The process of adaptive evolution is due to:

Expressed mutations Selection

What generalizations can we make about outcomes of models of selection against deleterious alleles (aka purging)?

F - 6.Both 2 and 3 are true. Selection in inbreeding populations will purge deleterious recessive mutations Inbreeding depression is reduced after several generations of inbreeding Rate of purging depends on opportunities for recombination

Starting at q = 0.9, how can you get the most rapid initial change in the frequency of the deleterious allele?

F - 6.Both 2 and 3.

Your study of microsatellite variation (neutral to selection) in sage grouse in eastern OR reveals the following results: - Year 1 allele frequency = 0.55 - Years 1 to 2 saw an increase in allele frequency by 0.2 - Years 2 to 3 saw a decrease in allele f Your study of microsatellite variation (neutral to selection) in sage grouse in eastern OR reveals the following results: Year 1 allele frequency = 0.55 Years 1 to 2 saw an increase in allele frequency by 0.2 Years 2 to 3 saw a decrease in allele frequency by 0.2 Based on these data, what can we say about allele frequency change in year 4?

F - 6.Nothing at all.

A group that includes species A,B and C but not their common ancestor is

Groups without the elbow (node)

Molecular data demonstrate that different genes with unrelated functions can have high sequence similarity in their untranscribed regions indicating that they were derived from a common ancestral sequence. This is an example of:

Homology

You are working with a rare-checker spot butterfly that is suffering population decline. Your genetic analyses have revealed a new completely recessive advantageous allele that occurs at very low frequencies. Managers have been outbreeding to avoid inbreeding depression. What would be the best solution to increase the frequency of the advantageous allele?

Increase population size increase levels of inbreeding

Why is sexual reproduction advantageous?

It allows for recombination It may be advantageous in changing environments

In a population subject to genetic drift you have seen the frequency one allele increase five generations in a row. What can you predict about what will happen in the sixth generation?

It is not possible to make this prediction

Why was the revelation of the Hardy-Weinberg principle important for evolutionary biology?

It provided prediction and testable hypothesis It provided a starting point of the development of a mathematical foundation for evolution

The first person to propose a theory based on the idea that species can change over generations was:

Jean-Baptiste Lamarck

The person(s) responsible for the Neutral Theory of Evolution were:

Motoo Kimura

Phylogenies constructed from DNA sequences:

Must use orthologous genomic regions Nucleotides are used as traits

Evolution in a population may occur due to....

Mutation Migration - Migration can overwhelm the effect of selection but not genetic drift. Genetic drift may overwhelm the effects of selection and migration in small populations. Selection - Selection controls the rate of allele frequency change.

Gametic Disequilibrium *also known as linkage*

Non-random association among alleles at separate loci -Observed frequencies of alleles occurring together differs from the random expectation. -Alleles at linked loci are more likely to be in disequilibrium, but linkage is not necessary for disequilibrium to be maintained. - If loci are unlinked, r = 0.5, D will be reduced by ½ each generation Alleles at unlinked loci may be in disequilibrium because of ◼ Selection ◼ Genetic drift, mutation ◼ Admixture (gene flow between species) - Recombination will eventually break-up associated alleles. (decrease with generation) ◼ The expected level of gametic disequilibrium is always zero.

For the same gene you find multiple copies in each bird species. These copies are referred to as

Paralogous genes

monophyletic

Pertaining to a group of taxa that consists of a common ancestor and all of its descendants. A monophyletic taxon is equivalent to a clade.

paraphyletic

Pertaining to a group of taxa that consists of a common ancestor and some, but not all, of its descendants.

You measure coat color in rabbits over one year and find that they become lighter in color in the fall. You have demonstrated:

Phenotypic plasticity.

The dark and white morph in the pepper moth is controlled by a single locus. This is an example of:

Polymorphic trait

Allele frequencies do not change from one generation to the next. What do we have to assume to make this true?

Population size is large There is no selection There is no migration

You compare sequence data for two closely related species of warbler. For one particular gene, you find a higher substitution rates for the third codon position compared to the first and second. You have demonstrated

Purifiying selction

The frequency of sequence differences for comparisons among species is lower for codon position 1 and 2 because....

Purifiying selection (codon 3 can be changed freq)

The following is true of Macroevolution

Refers to diversification of new species and lineages Differs from microevolution by occurring over a longer time scale

For an unlinked pair of allele's, the gametic disequilibrium is reduced by 1/2 each generation because

Repulsion phase allele combinations are converted to coupling phase Coupling phase allele combinations are converted to repulsion phase recombination occurs in double heterozygotes

Which is a mutation?

Sequence changes: In/del, Base substitution Gene duplication Inversion Chromosomal: Translocation, Aneuploidy, polyploidy

Mutation rates are generally

Similar for plant and animal nuclear genomes Lower for plant chloroplast genomes Higher for animal mitochondrial genes

You sample a population of spotted towhees in Forest Park in the spring and find they are variable for beak width. Over the summer there is mortality of birds, so by the end of the summer you find the population is smaller. mean beak width is the same, but the range of variation in the beak width is much lower than it was in spring. What have you demonstrated?

Stabilizing selection

The factors primarily responsible for rapid evolution of HIV are

Strong selection High mutation rates large numbers are produced each generation

To construct a phylogenetic tree you will need:

Synapomorphic traits.

What contributes to fitness(w) of an individual?

The ability to survive adulthood The number of offspring produced Survival of offspring produced

Low rates of recombination results in

The accumulation of deleterious mutations selective interference

In the continent-island model of migration, the equilibrium for q on the island depends on

The allele frequency on the continent

The consequences of a population bottleneck for loss of rare alleles depends on.... 1. The population size before the bottleneck. 2. The number of founders after the bottleneck. 3. Loss of rare alleles cannot be predicted. 4. Both 1 and 2 are true. 5. Both 2 and 3 are true. 6. Both 1 and 3 are true. 7. All, 1, 2, and 3 are true.

The number of founders during/after the bottleneck Greater for loci with more alleles Rare alleles more likely to be lost

In a phylogeny the branch lengths depend on

The number of nucleotide base substitutions that differ between species

You are working with endangered pigmy rabbits. After sampling a population and assaying for genetic markers you find the average Ho = 0.25 and you estimate He = 0.50. What is the most likely cause of this difference?

The rabbits are inbreeding Genetic marker: a defined genomic location that can be assayed

You are working with endangered pigmy rabbits. After sampling a population and assaying for genetic markers you find the average He = 0.43 and the average Ho = 0.25. What is the most likely cause of this difference? 1. Population size is very large. 2. High gene flow among populations. 3. High levels of genetic drift. 4. Low gene flow among populations. 5. There is strong selection. 6. The rabbits are inbreeding. 7. Overdominance.

The rabbits are inbreeding Mating between closely related individuals will decrease the frequency of heterozygotes. The inbreeding coefficient can be defined as: f = 1 - (Ho/He) F = HE - HO If the observed (Ho) and expected (He) proportions of heterozygotes are identical then f = 0.

You select on "tameness" in foxes to try to produce a domestic fox. The response to selection in the next generation will depend on:

The strength of selection The heritability of the trait

Observed numbers of mutation are higher for introns and intergenic regions because...

They are unlikely to be affected by selection (silent)

Concerning indels we can say

They may evolve by selection or genetic drift They are the deletion or insertion of one or more base in the DNA sequence

Homoplasy results from

Trait reversal Convergent evolution

Homology refers to

Traits derived from the same ancestral trait

What are pseudogenes?

Turned off after duplication randomly accumulate mutations at the same rate as introns

What contributes to genetic load of a population?

Variation for alleles that affect fitness The presence of deleterious recessive mutations The mutation rate in the population dominance, overdominance, epistasis

HW principle assumptions

Very large population Random mating No selection No mutation, migration or drift provides description of genetic composition of diploid predictable, clear testable hypothesis p2 + 2pq + q2 = 1. Populations will not necessarily return to the original equilibrium after a perturbation. Heterozygotes are most abundant if p = q = 0.5 if p or q are close to 1.0. - Nearly all of the less common alleles are present only in heterozygous genotypes.

Many species of snakes have small bones that do not articulate with the skeleton at the end of the spine where the tail starts. This is an example of:

Vestigual trait

The controversy between the biometricians and Mendelians:

Was resolved when both the Mendelians and Biometricians were proved correct by fisher

In red tailed hawks, white (W) is dominant to black (w). In a population of 100 hawks you find 4 black ones and you estimate the frequency of w as 0.20, is this estimate accurate based on the information you have?

Yes if there is no selection Yes if there is no migration Yes their population size is very large

What is Muller's Ratchet?

accumulation of deleterious mutations in lineages that lack genetic recombination Inbred/isolation population

plesiomorphic

an ancestral characteristic or trait that is shared by two or more taxa 1 1 1 1 1

apomorphic

derived characteristics that arose relatively late in members of a group and therefore differ among them; 1 0 0 0 0

Detrimental alleles (starting at q = 0.3) will decrease in frequency faster: a. As s (selection strength) increases b. As h (dominance) increases c. As s decreases d. As h decreases e. When both 1 and 2 are true. f. When both 1 and 4 and true g. When both 3 and 2 are true

e. When both 1 and 2 are true. Reasoning: Strong selection will rid us of the homozygous recessive alleles, and the heterozygous alleles will decrease with stronger dominance (h)

The heterozygosity of a population several generations after a bottleneck depends on.....

heterozygosity of the population before the bottleneck The number of founders during the bottleneck population growth rate after the bottleneck

A feasible and effective way to accelerate the reduction in D in a population would be......

increase outbreeding

A group that includes species A and B (closest together)

monophyletic

Lines on phylogeny tree join at

nodes

polyphyletic

pertaining to a group of taxa that includes distantly related organisms but does not include their most recent common ancestor

In red tailed hawks, (W)white is dominant to black (w). In a population of 100 hawks you find 4 black ones. What is the allele frequency (q) of w?

q= sqrt(0.04)

Crossing over in meiosis results in

recombination

Allele frequency change in very large populations is most strongly to be affected by.....

selection - not drift or mutations if the population is large allele: a variant segregating at a locus.

For a deleterious reccessive (h=0) allele at frequency q, when would you expect delta(q) to be lowest?

when q is close to 1.0 when q is close to 0