Cycle 6

Question 1

How allele frequencies change within a population

Answer 1

Population genetics (evolutionary genetics/microevolution)

Question 2

A ______ is a collection of families

Answer 2

population

Question 3

T/F news: people with naturally blonde hair are going to go extinct/the apple associated with blonde hair in humans is most likely to go instinct by 2202

Answer 3

FALSE

Question 4

The fake news stated that the problem is that blonde hair is caused by:

Answer 4

a recessive allele gene coding for hair color in humans

Question 5

If we start with a common dominant allele (p=0.6) and a rarer recessive allele (q=0.4), with no selection, how will allele frequencies change?
A) The dominant allele will increase in frequency and the recessive allele will disappear
B) Allele frequencies will stabilize at 0.75 dominant, 0.25 recessive
C) Alllele frequencies will stabilize at 0.50 dominant, 0.59 recessive
D) Allele frequencies will not change

Answer 5

D) Allele frequencies will not change

Question 5

When there is selection against a dominant allele, selection will:

Answer 5

remove every single copy of the dominant allele from the population

Question 6

In the absence of selection, if all the genotypes are equally fit, the fact that the allele is a recessive DOES NOT or DOES change its frequency in the population

Answer 6

DOES NOT

Question 7

The alleles______ ______ does NOT affect its frequency if there is no selection going on

Answer 7

dominance status

Question 8

Simply being recessive in the absence of selection doesn’t affect allele _______

Answer 8

frequencies

Question 9

Weaker selection would just take _____ to remove every copy of the dominant allele

Answer 9

longer

Question 10

_______ will increase to a frequency of 1, ______ to 0

Answer 10

Recessive, dominant

Question 11

Selection against the dominant allele increases or removes genetic variation?

Answer 11

Removes

Question 12

under heterozygote advantage, is the population evolving?
Yes
Yes, at first, but not after allele frequencies stabilize
No

Answer 12

Yes, at first, but not after allele frequencies stabilize

Question 12

Situations where there is no complete dominance: If there are two alleles at a locus, can have __ different phenotypes

Answer 12

3

Question 12

This is because:

Answer 12

recessive alleles can hide in the heterozygotes

Question 12

They are Sheltered by _____

Answer 12

diploidy

Question 13

when there is selection against a recessive allele (dominant allele favored):

Answer 13

selection will not be able to remove every single copy of the recessive allele, the frequency will just decrease, but never 0

Question 14

Selection is not as effective in this case:

Answer 14

Selection against a recessive allele (dominant allele favored)

Question 14

If _____ is present, and genotypes differ in _____ then the dominant status of the allele does matter somewhat

Answer 14

selection, fitness

Question 14

Most genetic disorders are almost always going to be associated with _______ alleles

Answer 14

recessive

Question 14

Under heterozygote advantage, is the population experiencing selection?
Yes
Yes, at first, but not after allele frequencies stabilize
No

Answer 14

YES

Question 14

T/F recessive alleles are not necessarily always harmful, selection just removes all the copies of harmful dominant alles

Answer 14

TRUE

Question 15

______ would have a different phenotype than the homozygous

Answer 15

Heterozygous

Question 15

Harmful alleles will always ______ in frequency, but whether it’s to zero depends on whether the harmful allele is dominant or recessive

Answer 15

decrease

Question 16

______: situation where the genotypes differ in fitness

Answer 16

Selection

Question 16

______: change in allele frequencies

Answer 16

Evolution

Question 17

Can you have selection, without necessarily having evolution?

Answer 17

YES

Question 18

Selection against homozygotes does or does not maintain long-term genetic variation

Answer 18

Does Maintain long-term genetic variation

Question 19

In selection against _______: Doesn’t matter if you started with lots of copies of the dominant vs recessive allele

Answer 19

homozygotes

Question 19

In Selection against heterozygote: Whichever allele started off more ____ will disappear

Answer 19

rare

Question 20

In: Selection against homozygotes
Common allele decrease in frequency until it hits ___

Answer 20

0.5

Question 21

Selection against heterozygotes Increases or Removes genetic variation

Answer 21

Removes

Question 22

T/F Populations usually show clean “Mendelain” (1:2:1, 1:3:3:1) ratios of phenotypes or genotypes

Answer 22

FALSE: Populations DO NOT usually show clean “Mendelain” (1:2:1, 1:3:3:1) ratios of phenotypes or genotypes

Question 23

BUT, just as for a single family, knowing the distribution of parental genotypes in a population lets us predict the distribution of genotypes in the:

Answer 23

next generation

Question 24

_____ predicts the outcome of a cross between two parents and in a randomly-mating population

Answer 24

Punnet square

Question 24

Conditions of Hardy-Weinberg Equilibrium (5)

Answer 24

Large
Random-mating population
Where mutations are very rare
And there is no migration (gene flow)
Or no selection

Question 24

HWE formulas: freq of (A1A1) =

Answer 24

p^2

Question 25

If HWE conditions met then: (2)

Answer 25

-Allele frequencies will not change
-Genotype frequencies can be predicted from allele frequencies

Question 26

freq (A1A2) =

Answer 26

2pq

Question 26

If not:

Answer 26

the population is NOT at HWE at this locus
One or more HWE assumptions are violated and the population could be evolving

Question 27

freq (A2A2) =

Answer 27

q^2

Question 27

3 steps:

Answer 27

1) Use observed genotype frequencies to calculate allele frequencies
2) Use these allele frequencies to calculate genotype frequencies that we’d expect under HWE
3) Compare observed vs expected numbers of each genotype: is the population in HWE at this locus?

Question 27

is the population in HWE at this locus If observed and expected same: ___

Answer 27

YES

Question 27

If genotype frequencies can be predicted from allele frequencies, the population is:

Answer 27

at HWE (it is not evolving) at this locus

Question 28

Dominance status of an allele does not cause ______, but can affect response to selection

Answer 28

evolution

Question 29

In a population of 100 pigs, there are 36 homozygous dominant black pigs (genotype BB), 48 heterozygous black pigs (BR), and 16 homozygous recessive red pigs (RR). What is the frequency of the R allele?
A : 0.64
B : 0.4
C : 0.32
D : 0.16
E : 0.08

Answer 29

B : 0.4

Question 29

_______ principle helps identify whether a population might be evolving

Answer 29

Hardy-Weinberg

Question 29

Is it likely that evolutionary agents are acting on this population at the tasting gene locus?
A : Yes
B : No

Answer 29

A : Yes

Question 29

Different types of _____ have different effects on genetic variation; some remove alleles entirely, some maintain more than one allele at a locus

Answer 29

selection

Question 29

Allele T, associated with the ability to taste a particular chemical, is dominant over allele t, associated with the inability to taste it. After surveying 100 people, 36 people can taste the chemical and 64 are non-tasters. The “tasting” gene was sequenced from all of the people who can taste the chemical, and the results show that 24 of the tasters are homozygous and 12 are heterozygous. What is the frequency of the T allele in this population?
A : 0.8
B : 0.6
C : 0.3
D : 0.2

Answer 29

C : 0.3

Question 30

A population of peas has 4 % of individuals that have purple flowers because they are homozygous dominant for the A allele, and 32 % are light purple and heterozygous (AB). The rest of the individuals are white (BB). What is the frequency of the B allele?
A : 0.80
B : 0.72
C : 0.64
D : 0.32

Answer 30

A : 0.80

Question 30

Is this population in Hardy-Weinberg Equilibrium?
A : Yes
B : No

Answer 30

A : Yes