Evolution lecture 7 review

Question 1

What is migration?

Answer 1

movement of alleles between populations

Question 2

What is gene flow?

Answer 2

Transfer of alleles from the gene pool of one population to the gene pool of another population.

Question 3

Migration occurs when in the life cycle?

Answer 3

After the juvenile stage but before reaching maturation.

Question 4

Migration tends to __________ allele frequencies between populations.

Answer 4

homogenize

Question 5

Why does drift not lead to adaptation?

Answer 5

since it is simply the accumulation of random events. It is a non-selective mechanism.

Question 6

Drift results from the violation of which HWE assumption?

Answer 6

infinite population size

Question 7

sampling error

Answer 7

random discrepancy between theoretical expectations and the actual result.

Question 8

genetic drift

Answer 8

sampling error in the production of zygotes from a gene pool.

Question 9

Founder effect

Answer 9

allele frequencies on newly colonized island are likely to be different from the older, larger population from which they were derived from, by chance.

Question 10

Why are microsatellites good for measuring genetic drift?

Answer 10

neutral loci that should only change due to drift.

Question 11

Neutral theory of molecular evolution (Kimura):

Answer 11

suggests that number of neutral mutations that rise to fixation due to drift should outnumber the number of beneficial mutations that reach fixation due to natural selection.
Genetic drift, rather than NS, is responsible for most molecular evolution

Question 12

What is the most common type of non-random mating?

Answer 12

inbreeding

Question 13

What is the most extreme example of non-random mating?

Answer 13

selfing

Question 14

Inbreeding leads to a change in ________ frequencies but not a change in ________ frequencies.

Answer 14

1 - genotype

2 - allele

Question 15

inbreeding

Answer 15

where individuals mate with other individuals that are highly genetically related at a higher than chance rate.

Question 16

Inbreeding leads to accumulation of __________.

Answer 16

homozygotes

Question 17

bottleneck effect

Answer 17

occurs when there is a distaster of some sort that reduces a population to a small handful, which rarely represent the actual genetic makeup of the initial population. This leaves smaller variation among surviving individuals.

Question 18

Coefficient of inbreeding (F)

Answer 18

probability that 2 alleles in an individual are identical by descent.
(probability that both alleles come from the same ancestor allele in some previous generation)

Question 19

What are the genotype equations for the general analysis of inbreeding?

Answer 19

A1A1 = p2 (1-F) + pF
A1A2 = 2pq (1-F) 
A2A2 = q2 (1-F) + qF

Question 20

What is the max F value?

Answer 20

0.5 - selfing

Question 21

Calculate the F value for offspring of two half-siblings.

Answer 21

Refer to notes - 1/8

Question 22

inbreeding depression

Answer 22

ecreased vigour in terms of growth, survival or fertility following one or more generations of inbreeding.

Question 23

inbreeding depression usually results from the exposure of __________ recessive alleles to selection. The most extreme of these being ____ mutations.

Answer 23

1 - deleterious

2 - LOF

Question 24

What are mechanisms that have evolved in plants and animals to avoid inbreeding?

Answer 24

1 - genetically controlled self-incompatibility
2 - dispersal
3 - mate choice

Question 25

Inbreeding is unavoidable in ______ populations

Answer 25

small

Question 26

inbreeding is a common problem for _____ and _______ species and a problem for _______ _______ programs.

Answer 26

1 - rare and endangered

2 - captive breeding

Question 27

Genetic load

Answer 27

accumulation of deleterious recessive allleles

Question 28

mutational meltdown

Answer 28

synergistic interaction between mutation, population size and drift

Question 29

What are the measures of heterozygosity?

Answer 29

1 - genetic polymorphism

2 - allelic richness

Question 30

genetic polymorphism

Answer 30

the fraction of loci within a genome that have at least two alleles with frequencies higher than 0.01.

Question 31

allelic richness

Answer 31

average number of alleles per locus.

Question 32

rate of evolution

Answer 32

rate at which new alleles created by mutation are substituted for other alleles already present.

Question 33

substitution

Answer 33

fixation of a new allele (made by mutation), with or without additional mutational change.

Question 34

When ______ ______ is the only mechanism of evolution, the rate of substitution is equal to the mutation rate

Answer 34

genetic drift

Question 35

Selectionist theory

Answer 35

predict that for many genes in most populations, the rate of substitution will reflect the action of natural selection on advantageous mutations.

Question 36

When populations are subject to both ______ and _______ _____, smaller populations follow more diverse evolutionary paths.

Answer 36

1 - selection and genetic drift

Question 37

What are the three types of mutations with respect to fitness.

Answer 37

1 - deleterious
2 - neutral
3 - beneficial

Question 38

Early analyses of molecular evolution suggested that rates of change were _____ and _______ through time. These conclusions seemed to be in ______ with what might be expected under natural selection.

Answer 38

1 - high
2 - constant
3 - conflict

Question 39

The evolution of __________ conforms to the assumptions and predictions of the neutral theory.

Answer 39

pseudogenes

Question 40

synonymous mutations

Answer 40

mutations that do not result in amino acid changes.

Question 41

non-synonymous mutations

Answer 41

mutations that result in amino acid changes.

Question 42

The rate of evolution for _______ mutations is much higher than the rate of evolution for _________ mutations.

Answer 42

1 - synonymous

2 - non-synonymous

Question 43

negative selection

Answer 43

natural selection against deleterious alleles.

Question 44

positive selection

Answer 44

NS favouring beneficial mutations.

Question 45

SNP

Answer 45

point in the genome at which some individuals have one nt and others have a different one.

Question 46

Genes responsible for the most _____ cellular functions appear to have the lowest rates of replacement substitutions.

Answer 46

vital

Question 47

Rate of sequence change correlates with _______ time rather than ________ time

Answer 47

1 - absolute

2 - generation