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Molecular Ecology > Population Genetics > Flashcards

Population Genetics Flashcards

(72 cards)

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1
Q

what can pop geentics use theory to explain

A

origin + maintenance of gen vaqiration, patterns + structures of gen variaiton, changes in alleles + genotype frequencies

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2
Q

pop genetic

A

study of naturally occuring genetic diffs between orgs

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3
Q

what can polymorphisms infer

A

genotype from pheotype, spot mendelian ratios

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4
Q

are polymorphisms postivie, neutral or negative

A

often selecteviyl neutral

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5
Q

why is neutral diversity important

A

functional genetic variatio, increased pop growth + viablity (stops IBD, mutational meltdowns, loss of adaptive pot.)

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6
Q

why is neutral diversity not important

A

more gen diversity doesn’t increase fitness, not preven to decrease extinction risk, need to instead focis on functional gen diversity

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7
Q

allozyme

A

mol variant of an enzyme

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8
Q

population

A

group of org of the same sp. living in the same area

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9
Q

mendelian pop

A

group of inbreeding, sexually-reproducing organisms that share a gene pool

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10
Q

2 examples of mendelian populations

A

arctic char, hooper swam

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11
Q

determinants of allele frequency

A

mutation, gene flow, genetic drift, natural selection, inbreeding

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12
Q

inbreeding

A

breeding with indivs more closely related than chance

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13
Q

mutation

A

generates new alleles in a pop

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14
Q

silent mutation

A

occur naturally very often - most have no phenotypic effect

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15
Q

what mutations affect phenotype

A

deleterious, neutral, beneficial

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16
Q

substitutions/indels

A

mutations on non-coding regions have no effect on phenotypw

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17
Q

point mutation

A

single based in coding regions that is silent

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18
Q

chromosonal rearrangement

A

larger-scale mutatyions

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19
Q

what occurs to new mutations

A

most are lost, some are fixed, contribute to gen viaratiob

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20
Q

what are the 2 detemrinants of new mutant alleles

A

genetic drift, natural selection

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21
Q

directional selection

A

alleles causes higher fitness than others

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22
Q

balancing selection

A

when alleles effect fitness but neither is better than the other

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23
Q

negatively frequency dependant selection

A

when fitness of a phenotype decreases as it gets more common

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24
Q

sexually antagonistic selection

A

when alleles are good fro one sex but bad for the other sex

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25
selection that varies in time + space
allleles that are good for one habitat are bad for the other
26
null model
assumes nothing is occuring
27
what does a null model do
1. predicts gen variation in absence of mut, drift, gene flow, selection 2. compares mol data to predictions under HWE 3. if data deviates signfiicantly, explore why
28
assumptions of HWE
sexually diploid, discrete genes, no sexual diffs in allele frequency
29
other assumptinos of HWE to simplify biology
no mutation, drift, migration, selection, + random mating occuring (large pop, random union of gametes, normal Mendelian allele segregation, equal parent fertility, equal fertilising capacity of gamete, equal survival of all genotypes)
30
stable equilibrium
if HWE knowcked out a gen, it will return to stable after 1 gen of random mating
31
how many pot genotypes are there with 3 alleles
6 genotypes
31
how many pot genotypes are there with 4 alleles
10
32
random mating
% that 2 indivs that ,ate is the same for all pot. pairs of indivs
33
what ways does random mating deviate
viability selection, sexual selection, assortive mating (+inbreeding, pop structures)
34
viability selectiobn
indivs carrying non-viable alleles are less likely to be part of a pair
35
sexual selection
indivs carrying allleles are less likely to mate
36
assortative amting
indvis are more likely to pair w/ pheotypically similar mates
37
negative assorative mating
prefer mates of dissimilar phenotypes
38
how does inbreeding impact HWE
doesn't directly change allele frequency, increases homozyogisty to HWE expectation, impacts all loci + can cause IBD
39
how do pop structures cause non-random mating
indivs more likely to mate with a sub-pop, increasing homozyogsity (similar to inbreeding but on a longer scale)
40
why are inbreeding pop structures interesting
cause genome-wide deviation form GWE, can be detected w/ autonyous mol markers, lots of evolutioary + applied consequences
41
null expecteation of gen drift
allele frequency will change onver time and neutral alleles will eventually fixate (speed depends on pop size)
42
why can gen drift be bad
cause IBD + loss of adaptive pot
43
implications of drift in small pops
lose gen variation very quickles (faster than muts create them), allelic diversity of pop decreases, homozygosity increases
44
effective pop size
no. indivs that an idealised pop would need to have to experience drift at the same rate as a real pop
45
idealised pop
pop with equal no. males + females - all indvs can reproduce, no. breding indvs constant from 1 gen to the next, random mating
46
what do bottlenecks do to effective pop (Ne)
to drop- cause rapid loss of gen variation
47
bottleneck
pop size recovers later but alleles are lost + homozyogisty is higher after recovery
48
founder effect
small no. founders disperse to form new pop + not all alleles are transferred when forming new pop
49
why do phenotypes + genotypes change in panmictic pops
natural selection, drift, mutation
50
panmixia
random mating within a breeding pop
51
what does no gene flow do to a panmictic pop
if divergence present, becomes greater over time
52
what does medium gene flow to do a panmictic pop
divergence is lessened, barriers difficult to pass + will have some mixing but still divergence
53
what causes medium gene flow
limited no. migrants exchanged in each gen: reproduce + gene flow, pop alleles frequencies change
54
what does high gene flow causes to a panmictic popualtion
no differentiation, allele frequency change over time
55
population genetic structure
the extent to which sub-pops are genetically differentiated from each other
56
what can you use population genetic structure for?
testing if pops are panmictic, if pops are limited in migration, testing sub-sp, finding recolonisation pathways, finding traits for life histories
57
extremes of pop genetic structure
total isolation, restricted gene flow, panmixia
58
assumptions of wright's island model
same size sub-pops, completely isolated
59
what 2 factors does FST depend on
migration rate + effective pop size
60
FST
measure of extent of differentiation between subpops
61
more complicated models than the island model
mainland island model, island model, stepping stone
62
wahlund effect
reduced heterozygosity overall due to sub-pop structure
63
FIS
measure of homozygous excess in indies relative to if HWE was met
64
what does FST=0 mean
no genetic differentiation (panmixia)
65
what does FST=1
all genetic variation is present
66
why is FST a bad measure of pop structure
dependance on within-pop diversity
67
why is FST a good measure of pop structure
can easily describe using1 figure
68
what case study studied the concept of IBD
Iberian white throated dipper
69
is FST a proof of local adaption
no
70
why do sub pops diverge over time
drift + sometimes selection
71

Molecular Ecology (8 decks)

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