Quantitative Genetics

Question 1

linkage disequilibrium

Answer 1

the occurrence of combinations of allies or genetic markers in a population more ore less often then would be expected from random haplotype formation from alleles based on their frequencies

Question 2

Random discrepancy between theoretical expectations and actual results is

Answer 2

sampling error

Question 3

Mutations come in four kinds:

Answer 3

1. lethal
2. deleterious
3. neutral
4. beneficial

Question 4

transfer of alleles from
the gene pool of one population to the gene pool of
another population, aka “gene flow”.

Answer 4

Migration

Question 5

In the Hardy-Weinberg model, genetic drift results from

Answer 5

violation of the

assumption of infinite population size.

Question 6

Genetic drift lead to

Answer 6

changes in allele

frequencies.

Question 7

Genetic drift has a more rapid and dramatic effect on allele frequencies in _____
populations than in ______ populations.

Answer 7

small, large

Question 8

The wandering of allele frequencies produces two important and related
affects:

Answer 8

1. Eventually alleles drift to fixation or loss, and

2. The frequency of heterozygotes declines.

Question 9

the number of breeding individuals in a
population that would show the same amount of dispersion of allele
frequencies or inbreeding as the population under consideration under
random genetic drift.

Answer 9

Effective population size -

Question 10

______is the creation of a new allele; is the fixation of the new
allele, with or without additional mutational change.

Answer 10

mutation , substitution

Question 11

Neutral theory -

Answer 11

Holds that advantageous mutations are exceedingly rare and

that most alleles of most genes are selectively neutral.

Question 12

Selectionist theory -

Answer 12

Holds that advantageous mutations are common enough

that they cannot be ignored.

Question 13

When mutation, genetic drift, and selection interact, three

processes occur:

Answer 13

1. Deleterious alleles appear and are eliminated by selection.
2. Neutral mutations appear and are fixed or lost by chance; and
3. Advantageous alleles appear and are swept to fixation by selection.

Question 14

Functionless stretches of DNA that result from gene duplication
events.

Answer 14

Pseudogenes -

Question 15

suggests that some

synonymous mutations are not selectively neutral.

Answer 15

Codon bias (strongest in highly expressed genes)

Question 16

Hitchhiking/Selective Sweep -

Answer 16

Can occur when strong positive selection acts on
a particular amino acid change.
• As a favorable mutation increases in frequency, neutral or even slightly
deleterious mutations closely linked to the favored site will increase in
frequency along with the beneficial locus.

Question 17

refers to the effect deleterious recessive alleles (in

homozygotes) have on the average fitness of offspring in the population.

Answer 17

Inbreeding depression

Question 18

Human activity did two things to the panther.

Answer 18

1. It directly reduced the size of the cat’s population.
2. It isolated the cat from other puma populations that it is closely related to—and
   that it once interbred with.

Question 19

If the problem for the Florida panther is reduced genetic diversity, then the solution
is gene flow. how to fix?

Answer 19

Migrants from other populations should bring with them the alleles that have been
lost in Florida.
Reintroduction of these lost alleles should reverse the effects of drift and eliminate
inbreeding depression.

Question 20

Two mechanisms of gene duplication are thought to be among the most common
sources of new genes. !

Answer 20

1. Unequal crossing over!

2. Retroposition or retroduplication!