aaaa

Yes, but very slowly

* Can mutation ALONE change allele frequencies over time?

Yes

* Can selection ALONE change allele frequencies over time?

Familial adenomatous polyposis

A DISEASE In Humans that is maintained BY MUTATION selection

population bottleneck

A brief period of reduced population size is called a ____________________

only a subset of alleles in the original population are represented in the newly founded population.

A founder event changes allele frequencies because

genetic variation

A loss of heterozygosity suggests decreased _________________, and this may be an indication of potential "trouble" for a population

Substitution

A new allele that arose through mutation becomes fixed in the population (replaces all other alleles)

0.0043

A new mutation arises in a population of spiders (which are diploid) with an effective population size of 116. If that mutation is neutral, what is the probability that it will go to fixation?

0.4167

A rancher genotypes all of her 150 head of cattle. In her herd, 25 are A1A1, 75 are A1A2, and 50 are A2A2. Assuming there is random mating, no selection, no mutation, and no new cattle are introduced into the population, what is the probability that the A1 allele will be fixed?

genetic drift

A researcher examines a microsatellite locus in a wild population of D. melanogaster. She finds that in a sample of 50 individuals, 20 different alleles are segregating. According to the neutral theory, these

All the escape behavior alleles are fixed in the population.

A researcher tracks the escape behavior of a population of squirrels on campus across two generations. When she plots the escape behavior of the offspring generation against the parental behavior, she notes that the offspring's behavior exactly matches the parental behavior. Nonetheless, the narrow-sense heritability equals zero. How can the heritability equal zero in this example?

low fitness

An individual mapped within an adaptive landscape as a point located in a fitness valley would be characterized as having

selection , mutation

Both ______ and ________ can lead to changes in allele frequencies over time

alleles

Bottlenecks can even result in the loss of certain _________.

total; total phenotypic

Broad-sense heritability is defined as the ________ genetic variation divided by the ________ variation.

Yes

Can migration ALONE change allele frequencies over time?

NO , but it changes genotype frequencies

Can non-random mating ALONE change allele frequencies over time?

freq. of heterozygotes : decrease Req. of homozygotes : increase

Consequences of assortative

Freq. of heterozygote : increase Freq. of homozygotes : decrease

Consequences of disassortative mating

The source population has a higher frequency of the A1 allele at generation zero than the island population.

Consider a locus with two alleles in an island population, where all assumptions of the Hardy-Weinberg model are met except "no migration." The figure shows the change in the frequency of the A1 allele over several generations. What can you say about the population that is the source of migrants to the island?

0

Consider a locus with two alleles, A and a. If the rate of mutation from A to a is twice the rate from a to A, what will be the equilibrium frequency of the A allele? (Assume that there are no other evolutionary forces acting on these alleles. Recall that the equilibrium allele frequency under mutation is p* = v/(m + v), where p* is the equilibrium frequency of the A allele, m is the rate of mutation from A to a, and v is the rate of mutation from a to A.)

0.2857

Consider a locus with two alleles, A and a. If the rate of mutation of A to a is 0.0000025 and the rate of mutation of a to A is 0.0000010, what will be the equilibrium frequency of the A allele? (Recall that the equilibrium allele frequency under mutation is p* = v/(m + v), where p* is the equilibrium frequency of the A allele, m is the rate of mutation from A to a, and v is the rate of mutation from a to A.)

the founder effect

Consider a population of lizards living on the coast of Africa. A storm creates piles of debris that the lizards use to raft to a faraway uninhabited island. Which evolutionary process is happening?

Migration

Excluding all other evolutionary forces, __________ ALONE tends to homogenize allele frequencies

the change in identity by descent over time.

F-statistics can be used to quantify the effects of genetic drift by measuring

Selection

Finally, if genetic variation is NOT neutral, ________ can favor one allele over others

0.000625

Five percent of quarter horses in the United States are heterozygous for the recessive lethal allele that causes glycogen branching enzyme deficiency (GBED). Assuming that quarter horses are randomly mated, this means that the frequency of this allele is q = 0.025. If the GBED allele is maintained in the population by mutation-selection balance, what is the mutation rate to the disease allele? (Recall that the equilibrium frequency for a recessive allele under mutation-selection balance is q = n m/s, where m is the rate of mutation to the disease allele and s is the selection coefficient against that allele. In the case of a lethal allele, s = 1.)

allele frequencies

Genetic drift causes changes in

random

Genetic drift is caused by ________ processes.

reduce

If alleles can be lost due to genetic drift, then we can conclude that drift can ___________ genetic variation

0.5.

If neutral mutations occur at the rate of 0.5 per individual per generation, the rate of neutral substitutions per generation in that population will equal

decrease

If the frequency of one allele decreases substantially relative to the other, then the number of heterozygotes will ______________

ABc

If we are interested in the A, B, and C loci of a diploid organism, which of the following would be a possible haplotype?

1 million years ago

Imagine that, of three species, it is known that species 1 and 3 were separated 10 million years ago, based on geologic measurements. Genetic analysis at a neutral locus indicates that these species differ by 100 substitutions. If there are 10 substitutions separating species 1 and 2, approximately how long ago did these species diverge?

fluctuate

In a finite population, allele frequencies _____________ over time, even in the absence of selection

epistasis

In a population of dragonflies, wing structure is determined by two loci (A, B), each with two alleles (A and a, B and b). Abnormal wings are produced in aa individuals unless they possess at least one B allele. This is an example of what evolutionary phenomenon?

Mutation

In contrast, _________ provides a continual supply of new genetic variation

the narrow-sense heritability

In the figure depicting heritability of migratory timing in the blackcap warbler, what does the straight line indicate?

They will become more similar to those on the mainland.

In the scenario depicted in the figure, what will happen to the allele frequencies on the island? Assume there is no selection or mutation, mating is random, and the population sizes are large.

homozygotes

Inbreeding increases the frequency of ________ in a population.

selectively neutral

It is useful to start the study of genetic drift with the idea that alleles under consideration are ___________

disassortative mating

MATING OF INDIVIDUALS W/ DIFFERENT GENOTYPES OR PHENOTYPES

assortative mating

MATING OF INDIVIDUALS WITH SAME GENOTYPE OR PHENOTYPE

persist

Many Genetic DISEASES _________ in Mutation - SELECTION BALANCED

Wright's F statistic

Measures the correlation between the two homologous alleles in a single individual

Wright's F statistic

Measures the fraction of the population that goes into the inbred pool

Allele frequencies

Migration affects ____________ in populations

selectively neutral

Most changes in the DNA or amino acid sequence over time are _____________, including differences between species

selectively neutral

Most of the variation present in a population is _________

Effective neutrality

Natural selection cannot operate effectively on mutations that have extremely small fitness consequences (positive or negative)

reduces the effective population size.

Population bottlenecks can result in rapid fixation or loss of alleles in otherwise large populations because the bottleneck

a consistently large population experiences a brief period of small size.

Population bottlenecks occur when

heterozygous

Quantifying heterozygosity in a population When more than one allele is present, some individuals will be ___________

UUG ® CUG

Refer to the figure of the genetic code shown to answer the following question. Which of the following mutations to a codon is most likely to be selectively neutral?

Founder effect

Sampling effect that occurs when a small number of individuals migrate and start a new population

the effect of genetic drift is stronger in small populations

Sampling error is larger in small samples, so... ______________

independently

Separate populations diverge in allele frequencies, that is: they vary ______________

decreases

Some alleles may be fixed and others lost, and the frequency of heterozygotes usually _____________

population size

The Wright-Fisher model was developed to study the evolutionary effects of ______________

individuals contribute unequally to future generations.

The effective population size is often lower than the census size of a population because

purifying selection

The figure shows aligned homologous gene sequences from two species. What is the dominant evolutionary force acting on this gene in these species?

They have experienced purifying selection in the tarweeds and positive selection in the silverswords.

The figure shows the Ka /Ks values for two regulatory genes in pairs of species in (A) North American tarweeds and (B) Hawaiian silverswords. The dashed lines are the mean Ka/Ks values. What do these data indicate about how these genes are evolving differently in these two groups of taxa?

The northern elephant seals experienced a population bottleneck, but the southern elephant seals did not.

The figure shows the level of diversity at three loci in two species of elephant seals. Which of the following could be true of these species according to the data?

Genetic drift is stronger in smaller populations.

The figure shows the relationship between the size of an island and the number of alleles found at microsatellite loci in lizard populations. What do these data demonstrate?

There are recessive deleterious alleles present.

The graph shows the relationship between the number of surviving gray wolf pups in a litter and the inbreeding coefficient of those pups. What do these data reveal about the types of alleles present in this population?

in highly diverged lineages, substitutions will occur at sites that have been substituted previously.

The molecular clock has limited usefulness for estimating divergence times among species in part due to the saturation of DNA sequences. This occurs because

higher in smaller populations.

The nearly neutral theory predicts that substitution rate is

the amount of variation expected in a population rate of non-synonymous / synonymous substitutions

The neutral Theory makes predictions about:

developmental noise

The phenotypic variation created by random chance events during the process of an organism's development is called

0.001

The rate of mutation to a recessive lethal allele is 0.000001. What is the equilibrium frequency this allele? (Recall that the equilibrium frequency for a recessive allele under mutation-selection balance is q = n m/s, where m is the rate of mutation to the disease allele and s is the selection coefficient against that allele. In the case of a lethal allele, s = 1.)

inverse relationship between generation time and population size.

The solution to the puzzle of why the rate of substitution is approximately constant per year, despite drastic differences in generation time among species, relies on the

The population sizes in the graph on top are smaller than the population sizes in the graph on the bottom.

The two graphs show the change in allele frequency, p, over 100 generations. Each graph shows 10 different populations, all experiencing the same evolutionary forces. What is the most likely difference between the populations shown in the top graph compared to the populations in the bottom graph?

assortative mating; disassortative mating

Under ________ individuals tend to mate with others of the same genotype. Under ________ individuals tend to mate with others of different genotypes.

remain the same but genotype frequencies do not

Under inbreeding, and in the absence of any other evolutionary mechanisms: allele frequencies ______________

when mating occurs mostly among close genetic relatives

Under which scenario will the presence of rare recessive deleterious alleles cause the greatest decline in fitness in a population?

Heterozygosity will decrease over time.

What is the effect of small population size on the degree of heterozygosity in a population?

0

When the alleles at all loci of interest occur independently, what will the value of linkage disequilibrium (D) be?

Epistasis

When the alleles at two or more loci interact in nonadditive ways, we refer to this as

physical linkage

Which of the following does NOT represent a way in which genotype and phenotype can interact?

reduced fitness of the population when there is inbreeding

Which of the following is a consequence of recessive deleterious alleles in a population?

A large population of frogs is greatly reduced due to a drought.

Which of the following is an example of a population bottleneck?

mutation and migration

Which of the following processes can increase genetic variation in a population?

genetic hitchhiking

Which of the following processes causes a neutral allele to increase in frequency because it is linked to an allele under selection?

narrow-sense heritability

Which of the following reflects the degree to which offspring resemble their parents in a population?

Selfing

______ is one extreme of a broad continuum, the other is purely random mating

Mutations

________ can happen in any part of the body at different rates within and between species

Selfing

_________ is the most extreme type of inbreeding.

Genetic drift

__________ decreases heterozygosity and increases homozygosity, so "in theory" any finite population could eventually become entirely homozygous

Mutations

___________ can change allele frequencies in a population * It is often the case that one of the two rates below is negligible

GENETIC DRIFT

_______________ can be considered a critical process in evolution

Inbreeding depression

_______________ occurs when the offspring from genetic relatives have reduced fitness

Inbreeding

a form of assortative mating

Evolution

change in allele frequencies in a population over time

mutation-selection balance

describes an equilibrium in the frequency of an allele that occurs because new copies of the allele are created by mutation at exactly the same rate that old copies of the allele are eliminated by natural selection

does not , genotype frequencies

non-random mating _________ change allele frequencies but it changes ____________ from what we expect under the HW model

genotype

non-random mating disrupts equilibrium of ________frequencies

Genetic Drift

random fluctuations in allele frequencies due to sampling effects in a finite population