Midterm 1 Content

Question 1

Mechanisms of evolution

Answer 1

genetic drift
natural selection
migration (gene flow)
mutation

Question 2

hardy Weinberg equilibrium allele frequency

Answer 2

p+q=1

Question 3

hardy Weinberg genotype frequency

Answer 3

p^2 +2pq+ q^2

Question 4

HW assumptions

Answer 4

no mutations
no natural selection
infinite population size
no migration
random mating

Question 5

mutations

Answer 5

ultimate source of genetic variation

Question 6

causes of mutations

Answer 6

errors in DNA replication, mitosis, meiosis. damage to DNA

Question 7

silent

Answer 7

3rd bp, doesn’t change amino acid

Question 8

silent mutation is synonymous

Answer 8

mutation, but same amino acid

Question 9

nonsense

Answer 9

encodes stop codon

Question 10

nonsense is nonsynonymous

Answer 10

mutation, different amino acid

Question 11

organisms with larger genomes

Answer 11

higher mutation rate per base pair per genotype

Question 12

silent mutation

Answer 12

mutations with no effect on phenotype

Question 13

neutral mutation

Answer 13

mutations with no effect on fitness (reproductive success)

Question 14

natural selection

Answer 14

any consistent differences in fitness among different classes of biological entities

Question 15

Conditions for natural selection

Answer 15

reproduction
variation
inheritance
differential success

Question 16

positive selection

Answer 16

selection for an allele that increases fitness

Question 17

Positive selection impact on genetic variation

Answer 17

Tends to reduce genetic variation

Question 18

selection coefficient (s)

Answer 18

measure of differences in relative fitness among genotypes

Question 19

higher s results in

Answer 19

stronger selection and faster evolution

Question 20

mean fitness of genotype in population

Answer 20

when hetero has highest fitness

Question 21

selective sweeps

Answer 21

a mutation increases in frequency, leads to reduction or elimination of genetic variation near selected mutation (temporarily)

Question 22

linkage disequilibrium

Answer 22

measure of non random associations between alleles at different loci

Question 23

What kind of LD after sweep

Answer 23

high LD after sweep

Question 24

Types of balancing selection

Answer 24

overdominance
negative frequency dependent selection

Question 25

over dominance

Answer 25

hetero advantage

Question 26

negative frequency dependent selection

Answer 26

fitness of allele/geno/pheno decreases as it becomes more common (rarity favored!!)

Question 27

mutation selection balance

Answer 27

equilibrium frequency, q, of deleterious alleles we would expect to see in a population

Question 28

genetic drift

Answer 28

random changes in frequency of alleles in population

Question 29

factors of genetic drift

Answer 29

survival reproduction inheritance

Question 30

effects of drift

Answer 30

drift causes fixation of an allele at a probability equal to its starting frequency

Question 31

what frequency do new alleles have that have just risen

Answer 31

1/2Ne

Question 32

genetic drift fundamentals

Answer 32

-drift is unbiased -stronger in small populations -causes genetic variation to be lost -causes populations initially identical to be different -an allele can become fixed without natural selection

Question 33

how strong is drift?

Answer 33

strong in: -small populations -populations that fluctuate in size -populations with larger proportions of non reproductive individuals (social insects) - unequal # of reproducing M/F

Question 34

effective population size (Ne)

Answer 34

size of an idealized population that would experience same level of genetic drift as observed population

Question 35

large Ne

Answer 35

drift weak

Question 36

small Ne

Answer 36

drift strong

Question 37

polymorphism

Answer 37

more than 2 genotypes in a population

Question 38

mutation in coding region

Answer 38

non synonymous and removed through purifying selection - lower heterozygosity

Question 39

synonymous mutations and mutations in non coding regions

Answer 39

higher heterozygosity not impacted by selection

Question 40

population bottle neck

Answer 40

number of individuals reduced drastically, can have lasting effects on genetic variation of population

Question 41

founder effect

Answer 41

type of genetic drift variation accompanies founding of new population from small number of individuals

Question 42

consequences of drift (1/Ne) on selection (greater than)

Answer 42

s>> 1/Ne selection stronger when Ne is large

Question 43

consequences of drift (1/Ne) on selection (less than)

Answer 43

s<<1/Ne drift is stronger when Ne is small

Question 44

consequences of drift: divergence

Answer 44

Number of new mutations/locus/gen: 2Nmu

Question 45

divergence

Answer 45

speed at which mutations fixed across population is proportional to mutation rate

Question 46

gene flow

Answer 46

incorporation of genes into gene pool of one population from one or more other populations

Question 47

effects of gene flow

Answer 47

can restore genetic variation to local population homogenize allele frequency among populations increase or decrease fitness of population

Question 48

how is gene flow measured

Answer 48

migration rate (m)

Question 49

difference between populations

Answer 49

Fixation index (Fst)

Question 50

measure of Fst

Answer 50

measure genetic difference between 2 or more populations

Question 51

plesiomorphy

Answer 51

ancestral character state

Question 52

apomorphy

Answer 52

derived character state

Question 53

importance of an outgroup

Answer 53

species or taxa that helps us determine which character states are ancestral or derived

Question 54

locus

Answer 54

physical location in/on a chromosome

Question 55

gene

Answer 55

a DNA sequence that encodes a product with a distinct function

Question 56

allele

Answer 56

variant

Question 57

genotype

Answer 57

the genetic constitution of an individual organism. for diploid individuals

Question 58

phenotype

Answer 58

a morphological, physiological, biochemical or behavioral characteristic of an individual (usually product of genotype and environment)

Question 59

pleiotropy

Answer 59

a phenotypic effect of a gene on more than one character