Exam 4 Vocab and Multiple Choice

Question 1

correlation

Answer 1

the strength of association between two measurements

Question 2

quantitative

Answer 2

a trait that is continuously variable over some measure

Question 3

inbreeding

Answer 3

preferential mating between related individuals

Question 4

regression

Answer 4

linear relationship between two variables

Question 5

allopatric

Answer 5

speciation is initiated when a geographic barrier splits a population into two or more groups

Question 6

variance

Answer 6

indicates the variability of a group of measurements

Question 7

bottleneck

Answer 7

when a population undergoes a drastic reduction in size

Question 8

mean

Answer 8

provides information about the center of the distribution

Question 9

positive assortative mating

Answer 9

tendency for like individuals to mate

Question 10

founder effect

Answer 10

establishment of a population by a small number of individuals

Question 11

sympatric

Answer 11

speciation arises in the absence of an geographic barrier to gene flow

Question 12

qualitative

Answer 12

a trait with only a few distinctive phenotypic classes

Question 13

One can estimate the number of genes underlying a trait by crossing two pure lines where the parents are extreme for the phenotype of interest. For example one parent is extremely small and the other parent is extremely large where it is assumed that the small parent is homozygous for all the “small” alleles and offspring will all be heterozygous. If one then intercrosses the F1 to produce the F2, the proportion of the F2 that resemble the parents phenotype is an estimate of the number of genes involved. If one did this experiment and found that 1/4096 offspring resembles the parents, how many loci are involved in determining the phenotype?
A) 2
B) 3
C) 5
D) 4
E) none of the above

Answer 13

E) none of the above (n=6)

Question 14

assuming a trait has a high narrow sense of heritability, which relationships would you expect to be most similar phenotype of the trait?
A) fullsibs
B) half sibs
C) 1st degree cousins
D) they’re all very different

Answer 14

A) full sibs

Question 15

bristle number in drosophila is a highly heritable trait with h^2 = 0.52. If the average bristle number in the parental population was 28.7 and you selected flies to produce the next generation that had mean bristle number of 30.5, what is the selection differentials?
a) -1.8
b) 43.6
c) 1.8
d) none of the above

Answer 15

c) 1.8

Question 16

A particular location on a chromosome, say chromosome 1 position 120,256,947 bp, has 3 alleles (A, C, and T) segregating in the population. If the frequency of allele A is 0.70, what if the frequency of the T allele?
a) 0.80
b) 0.20
c) 0.70
d) unable to tell base on the information given

Answer 16

d) unable to tell base on the information given

Question 17

What are the 5 main assumptions for a population to be in the Hardy-Weinberg Equilibrium?

Answer 17

• random mating
• no mutation
• no migration
• no selection
• no drift (large population size)

Question 18

If the Hardy-Weinberg Equilibrium assumptions are met, what two predictions can be made in a population in equilibrium?

Answer 18

• allele frequencies do not change
• equilibrium will be reached in one generation

Question 19

sampling error arises when gametes unite to produce progeny. The variance in allelic frequency at a locus is determined by the frequency of the alleles at that locus. Which of the following loci will have the largest variance in allele frequency?
a) locus 1 where p=0.40
b) locus 2 where p=0.70
c) locus 3 where p=0.30
d) unable to determine with the information provided

Answer 19

a) locus 1 where p=0.40

Question 20

what is the expected frequency of heterozygosity in a population with allelic frequencies represented by variables x any y that is in the Hardy-Weinberg equilibrium?
a) x+y
b) (x+y)^2
c) xy
d) xy/2
e) none of these

Answer 20

e) none of these (2xy)

Question 21

In cats, all-white color is dominant over colors other than all-white. In a population of 100 cats, 75 are all-white. Assuming that the population is in the Hardy-Weinberg equilibrium, what is the expected frequency of all-white cats homozygous for the all-white allele in this population?
a) 0.50
b) 0.25
c) 0.75
d) 0.125
e) none of these

Answer 21

b) 0.25

Question 22

When a population is in mutational equilibrium, which of the following is true?
a) the number of forward mutations is greater than the number of reverse mutations
b) the number of forward mutations is equal to the number of reverse mutations
c) no forward or reverse mutations occur
d) the population is in the HWE
e) none of these are true
f) two of these are true

Answer 22

b) the number of forward mutations is equal to the number of reverse mutations

Question 23

consider two large populations (A & B) and a bi-allelic locus with alleles at frequency p and q. In one generation, 10 random individuals migrate from population A to population B. What will happen to the allele frequency q as a result of migration when q is equal in both populations?
a) q in population A will decrease
b) q in population B will increase
c) q will not change in either population A or B
d) q in population B will become q^2
e) not enough information provided to answer correctly

Answer 23

c) q will not change in either population A or B