Cycle 6 part 2

Question 1

Heterozygote advantage and heterozygote disadvantage have two differences:

Answer 1

-Different effects on genetic variation

-Different importance of starting allele frequencies

Question 2

Heterozygote advantage and heterozygote disadvantage have in common:

Answer 2

both can only occur if heterozygotes have a different phenotype than either homozygote

Question 3

Heterozygote advantage and heterozygote disadvantage are not possible if one allele is completely _______ and the other is completely ________

Answer 3

Dominant and recessive

Question 4

Rare alleles are mostly in heterozygotes or homozygotes

Answer 4

heterozygotes

Question 5

Common alleles are mostly in heterozygotes or homozygotes

Answer 5

homozygotes

Question 6

Het advantage: rare alleles increase or decrease?

Answer 6

increase

Question 7

Het disadvantage: rare alleles increase or decrease

Answer 7

decrease

Question 8

A genotype’s ____________, W, is a measurable quantity (average lifespan, number of eggs, number of grandoffspring)

Answer 8

absolute fitness

Question 9

A genotype’s ________, w, is its absolute fitness divided by the absolute fitness of the most successful genotype

Answer 9

relative fitness

Question 10

If WAA = WAa=Waa what type of selection is occurring

Answer 10

No selection

Question 11

Genetic drift: random sampling error
Most powerful in ____ populations, but happens whenever population size is ____

Answer 11

small, finite

Question 11

Iclicker question: If WAA = 20, WAa = 15, and Waa = 12, what is the relative fitness of genotype aa? That is what is waa?

Answer 11

0.6

Question 12

Which situation describes heterozygote disadvantage?

Answer 12

WAA>WAa<Waa

Question 13

If wAA = wAa > waa what tu[e pf selection is occuring?

Answer 13

Selection against allele a

Question 14

T/F Genetic drift is restricted to bottlenecks and founder events…

Answer 14

FALSE: it is always happening

Question 15

If f(A) decreases and f(a) increases due to genetic drift in one generation, what will probably happen in the next generation?

Answer 15

f(A) and f(a) will probably change again, but we can’t predict which will decrease and which will increase

Question 16

CAN PREDICT: Over many generations, drift tends to _____ genetic variation

Answer 16

remove

Question 17

Usually, but not always, the ___ allele gets removed

Answer 17

rarer

Question 18

If mating is not random with respect to genotype: Like with Like at one trait is ______

Answer 18

Assortative mating

Question 19

Opposites attract at one trait:

Answer 19

disassortative mating

Question 20

Like with like genome-wide?

Answer 20

Inbreeding

Question 21

Opposites attract genome-wide?

Answer 21

Inbreeding avoidance

Question 22

Assoritve mating perturbs ____ but doesn’t cause ______

Answer 22

HWE, evolution (out of HWE but still not evolving because allele frequencies are not changing)

Question 23

Does inbreeding cause evolution?

Answer 23

NO

Question 24

If not, why are genetic disorders so common within highly inbred populations or inbred royal dynasties?

Answer 24

Most genetic disorders are associated with recessive alleles. So even though inbreeding doesn’t change the frequencies of the allele, it increases the proportion of homozygous recessive genotypes

Question 25

Homozygous ______ genotypes that are likely to express harmful alleles

Answer 25

recessive

Question 26

Iclicker questions: How can we determine whether a population is in HWE at a particular locus?

Answer 26

Calculate allele frequencies, and check whether these match the observes genotype frequencies

Question 27

In a pond of 100 fish: 16 are black (BB), 48 are gray (Bb), 36 are white (bb). What can you reasonably conclude about selection at this locus?

Answer 27

Selection is not occuirng

Question 28

In a flock of 100 birds, 5 have red feathers (RR), 90 have purple feathers (Rr) and 5 have blue feathers (rr), which of these explanations is most likely?

A) Because p = q, the population is in HWE at this locus. Therefore, selection is not operating on feather color

B) The population is either inbred or mating assortatively (like with like) at those locus

C) Heterozygote advantage at this locus

Answer 28

B