Exam 1 Lecs - 4 Flashcards
evidence of founder:
- Polynesian field crickets: native to … and …
found on …, including …
Australia;
New Guinea;
Pacific Islands;
Hawaii
evidence of founder:
Polynesian Field Crickets:
- Crickets dispersed across the Pacific Islands:
expectation is that there’s …/… on the islands, we expect to find … and we expect to see …/…
drift; founder events;
small number of alleles;
fixed/lost alleles
evidence of founder:
Polynesian Field Crickets:
Crickets dispersed across the Pacific Islands:
- Each island’s population would likely have been founded by a …
- sampled 394 crickets from 19 pops at seven … (…, can’t be under …, …)
small number of individuals; microsatellite loci; noncoding DNA; selection; neutral
evidence of founder:
Polynesian Field Crickets:
Crickets dispersed across the Pacific Islands:
- sampled 394 crickets from 19 pops at seven microsatellite loci (noncoding DNA, can’t be under selection, neutral):
microsatellites have many ….
Sampled mainland Australia and the pacific islands –> For the mainland samples, frequency of alleles was … But in Pacific Islands, we see … of …
easily identifiable alleles;
distributed more among numerous alleles;
higher frequency; fewer alleles
evidence of founder:
Polynesian Field Crickets:
Sampled mainland Australia and the Pacific Islands:
- For the mainland samples, frequency of alleles was distributed more among numerous alleles. But in Pacific Islands, we see higher frequency of fewer alleles –> islands have … and … alleles with … –> some alleles from mainland … in island populations
This is evidence of founder events and the impact of drift over several gens
less genetic diversity;
fewer;
higher frequencies;
aren’t present
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
- population made up of survivors of …
- … occurred also
- among survivors were carriers of a … allele in … cells
typhoon;
famine;
recessive loss of function;
cone
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
- among survivors were carriers of a recessive loss of function allele in cone cells (i.e. cells that enable us to see …) –> people with that gene have … cone cells and …
color;
non-functioning;
extreme sensitivity to light
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
Among survivors were carriers of a recessive loss of function allele in cone cells (i.e. cells that enable us to see color)
- completely … with … as well
- condition is called …
color blind;
poor vision;
achromatopsia
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
- Condition called achromatopsia: …, frequency is … people worldwide. However, in the Pingelapese the frequency is …
rare;
1/20,000;
1/20
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
- … by the typhoon, a founder event, left the allele at a frequency of at least …. It’s now more than …
sampling error;
2.5%;
20%
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
Sampling error by the typhoon, a founder event, left the allele at a frequency of at least 2.5%. It’s now more than 20%:
- this change in frequency: no … to island so no new alleles coming in, the key point though is = …(it’s …)
migration;
random drift;
increasing by chance
Evidence of founder:
Pingelapese people of Eastern Caroline Islands:
- this change in frequency due to random drift: when the population is very small, … is not strong enough to reduce frequency of the allele. … is stronger in smaller populations
selection;
drift
Evidence of founder:
controlled lab experiment on fruit flies:
Buri studied … and … empirically
random fixation;
loss of heterozygosity
Evidence of founder:
controlled lab experiment on fruit flies:
Buri studied random fixation and loss of heterozygosity empirically:
- established 107 pops of flies, .,.. and … as starting population
- All of the founders were … for brown eyes (allele …)
8 males;
8 females;
heterozygous;
bw75
Evidence of founder:
controlled lab experiment on fruit flies:
Buri established 107 populations of flies, 8 males and 8 females as starting population:
- he maintained these pops for … generations and kept the population size at … by picking 8 females and 8 males …
19;
16;
at random
Evidence of founder:
controlled lab experiment on fruit flies:
Buri maintained these pops for 19 generations and kept the population size at 16 by picking 8 females and 8 males at random –> what results would we predict for allele bw75? A: It can … or … since it’s …
Over the generations, most populations had either … the frequency of the allele or … the frequency of the allele
either increase; decrease; random;
fixed;
lost
Evidence of founder:
a controlled lab experiment on fruit flies:
Why is the number of populations with frequency 0 is approximately the same as frequency 1?
- partly bc its …
- primarily bc … of the allele was …
random;
initial frequency; 0.5
Evidence of founder:
controlled lab experiment on fruit flies:
Why is the number of populations with frequency 0 is approximately the same as frequency 1?
- primarily bc initial frequency of the allele was 0.5. From the beginning, half of the alleles were bw and half were bw75. Equal chances of either … or …
If initial frequency was about 0.9 for bw75, you’d expect to have more populations …
fixing;
being lost;
fixing the allele
Evidence of founder:
controlled lab experiment on fruit flies:
What happens to heterozygosity as bw75 is drifting toward fixation or loss in the population?
- …
- heterozygosity plot is similar to a … with …
decreases;
straight line;
negative slope
Evidence of founder:
controlled lab experiment on fruit flies:
… acted as one of the main forces of evolution in Buri’s flies and it was …
drift;
totally random
Evidence of founder:
Natural experiment looking at the same things:
Alan Templeton tested predictions about … in Missouri’s Ozark mountains
This region is now mostly forest and savannah nviro
between 8000 and 4000 ya, … invaded the desert region. But then, climate changed again and … began invading the region again
random fixation of alleles;
forest;
savannah
Evidence of founder:
Natural experiment looking at the same things:
Exposed rocky outcrops called the … In those isolated pockets of desert, can find populations of …
In the 50s, they … in this environment
glades;
collared lizards;
suppressed fire
Evidence of founder:
Natural experiment looking at the same things:
In the 50s, they suppressed fire in this environment:
- lizards could migrate between those outcrops when … occur. Suppressing fires … the lizards more - …
fires;
isolated;
stopped migration
Evidence of founder:
Natural experiment looking at the same things:
In the 50s, they suppressed fire in this environment:
- they then sampled the lizards and sequenced the DNA at MDH, mtDNA (mitochondrial) and rDNA(ribosomal), looking at … in those regions
- found that in several outcrops, the individuals were … genetically –> this is bc pop is …, there’s …, and alleles are being … and there’s no …
variants; all the same; small; drift; fixed; migration
Evidence of founder:
Natural experiment looking at the same things:
In the 50s, they suppressed fire in this enviro:
- found that in several outcrops, the individuals were all the same genetically. … in populations is also due to drift, too
- proposed that the nearly complete loss of … in those populations doomed the lizards to …
differences;
genetic diversity;
extinction
Evidence of founder:
Natural experiment looking at the same things:
- Proposed that the nearly complete loss of genetic diversity in those populations doomed the lizards to extinction: suggested that local extinctions would occur through two forces: …, changes in … and …
pathogens;
biological; physical environment
Evidence of founder:
Natural experiment looking at the same things:
- proposed that the nearly complete loss of genetic diversity in those populations doomed the lizards to extinction. Suggested that local extinctions would occur through two forces: pathogens, changes in biological and physical environment
- pathogens are an issue bc there can’t be any … without … –> if pathogen can kill one lizard from that population, since they’re all the same, it’ll ….
- Same reasoning for changes in enviro
selection;
genetic variation;
kill all of them
Evidence of founder:
Natural experiment looking at the same things:
- They surveyed more glades. Consistent with their expectations, … of the glades had …
2/3rds;
no lizards
Young and colleagues reviewed evidence of these processes among populations of various sizes:
- compiled data on three … and a … Plotted measures of … against …
flowering herbs;
tree;
diversity;
population size
Young and colleagues reviewed evidence of these processes among populations of various sizes:
Compiled data on three flowering herbs and a tree. Plotted measures of diversity against pop size
- there is a correlation where, as size increases, diversity … (vice versa too):
small sizes: drift …. as some alleles are fixed and others lost
size of population can be measured from …/… –> the …
increases as well;
removes variation;
genetic diversity; polymorphism;
effective population size
Effective pop size: size of an ideal … that would … at the same rate as an …
theoretical population;
lose heterozygosity;
actual population of interest
effective pop size:
measure of variation is proportional to … –> can measure population size with …
This is a … number though so the effective pop size is pretty much always … than the actual size
size of population;
genes;
theoretical;
smaller
effective pop size:
-For humans, all the genetic diversity we have among 7 billion people is actually equivalent to an idealized population size of … –> we’re …
100,000;
very similar
random drift:
bc fluctuations in allele
- frequency are random, every population follows a … evolutionary path
- Genetic drift is more … and … in small populations than large
unique;
rapid;
dramatic
random drift:
- Genetic drift is more rapid and dramatic in small populations than large: in small populations, have …
Bigger sample has … –> if you take a larger sample of a population, that sample is a … of that population
higher sampling error;
smaller error;
better representation
random drift:
- given sufficient time, drift can produce substantial changes in … even in populations that are … –> drift is … in larger populations but it still changes … with enough time (will be … needed for larger populations)
allele frequencies; fairly large; weaker; allele frequencies; more time
