Population Genetics

Question 1

Define evolution.

Answer 1

A change in ALLELE frequency from 1 generation to the next.

Question 2

Define a gene.

Answer 2

A transcription unit that encodes for FUNCTIONAL RNA which will be translated into a protein.

Question 3

What are the 4 evolutionary mechanisms?

Answer 3

1. Gene flow
2. Genetic drift [bottleneck, founder effect]
3. Selection [natural, sexual]
4. Mutation

Question 4

Which evolutionary mechanism do the other mechanisms depend on?

Answer 4

Mutation

Question 5

Why is mutation required for the other evolutionary mechanisms to work?

Answer 5

Mutation brings in the VARIATION that the other mechanisms rely on

Question 6

Allele frequency changes lead to ________ which leads to __________.

Answer 6

Allele frequency changes lead to DIVERGENCE which leads to SPECIATION.

Question 7

What effect does mutation have on genetic diversity?

Answer 7

Mutation increases genetic diversity.

Question 8

Mutations can be _________.

Answer 8

Mutations can be DELETERIOUS.

Question 9

Which evo. mechanism is mutation SLOWER than?

Answer 9

Selection

Question 10

Which evo. mechanisms have the SAME RATE as mutation?

Answer 10

1. Genetic drift

2. Gene flow

Question 11

What are 2 causes of mutation?

Answer 11

1. Mistakes in REPLICATION due to DNA poly not being 100% efficient.
2. Environmental damage to DNA triggers DNA repair which has an error rate.

Question 12

What is the PRODUCT of gene flow, drift, + selection?

Answer 12

Evolutionary/selective PRESSURE

Question 13

To understand if allele freq. are changing over time, we need to know what 2 things?

Answer 13

1. WHICH alleles are present.

2. The CURRENT frequency.

Question 14

What is Hardy-Weinberg Equilibrium used for?

Answer 14

To calculate the EXPECTED allele frequencies.

Question 15

Hardy-Weinberg uses the _________________ to predict the _______________ in the subsequent generation.

Answer 15

Hardy-Weinberg uses the ALLELE FREQUENCIES to predict the GENOTYPE FREQUENCY in the subsequent generation.

Question 16

What are Punnett squares used for?

Answer 16

To show the possible GENOTYPES of the progeny.

Question 17

What are the 3 assumptions used in H-W Equilibrium?

Answer 17

1. Mating [fusion of gametes] is RANDOM
2. Population is INFINITELY LARGE
3. Evolution is NOT occurring

Question 18

Why does the population need to be sufficiently large for H-W Equilibrium?

Answer 18

It ensures that the allele freq. changes are NOT DUE TO SAMPLING ERROR.
It shows that evolution is not occuring.

Question 19

What does the assumption “evolution is not occurring” mean in H-W Equilibrium?

Answer 19

There are NO CHANGES in allele frequency from one generation to the next.

Question 20

What happens to allele frequencies in a population bottleneck?

Answer 20

There is a sudden DECREASE in the # of allele copies in a population.

Question 21

If a gene IS in H-W Equilibrium, what does that mean for genes at other loci?

Answer 21

They may or MAY NOT be in H-W Equilibrium.

Question 22

What does p^2 + 2pg + q^2 provide us with?

Answer 22

A NULL HYPOTHESIS to compare our observed/measured data

Question 23

What are 3 examples of NON RANDOM MATING?

Answer 23

1. Inbreeding/assortative mating [like with like]
2. Disassortative mating [opposites]
3. Sexual selection [choosing the ‘best’ partner]

Question 24

What is genetic drift?

Answer 24

Changes in ALLELE FREQ. due to RANDOM MATING

Question 25

What is a VESTIGIAL trait?

Answer 25

A trait that has lost its ORIGINAL FUNCTION over evolutionary time

Question 26

For a trait to be STRUCTURALLY HOMOLOGOUS, it does not need to be identical in _________, just in ____________.

Answer 26

For a trait to be STRUCTURALLY HOMOLOGOUS, it does not need to be identical in FUNCTION, just in CONSTRUCTION.

Question 27

What are zygotes? What are their ploidy?

Answer 27

Fused gametes.

DIploid.

Question 28

What are gametes? What are their ploidy?

Answer 28

Sperm or ova.

HAPloid.

Question 29

Genetic drift will have a STRONGER effect on a ________ population.

Answer 29

Genetic drift will have a STRONGER effect on a SMALLER population

Question 30

Which evolutionary mechanism is mostly caused by chance/sampling error?

Answer 30

Genetic drift

Question 31

If a population is in H-W Equilibrium, then the allele frequencies are not changing. Why?

Answer 31

Because there is RANDOM MATING occuring in a SUFFICIENTLY LARGE POPULATION with NO EVOLUTIONARY MECHANISMS at work.

Question 32

If a population is NOT in H-W Equilibrium, it does NOT tell us that the gene is ________. It only tells us than an ___________ has been ___________.

Answer 32

If a population is NOT in H-W Equilibrium, it does NOT tell us that the gene is EVOLVING. It only tells us than an ASSUMPTION has been VIOLATED.

Question 33

H-W Equilibrium 
Step 1. \_\_\_\_\_\_\_ H-W.
Step 2. \_\_\_\_\_\_\_\_ to our \_\_\_\_\_\_\_\_\_.
Step 3. Has an \_\_\_\_\_\_\_\_\_\_\_ been \_\_\_\_\_\_\_?
Step 4. Use your analysis to set up the \_\_\_\_\_\_\_\_\_\_.

Answer 33

H-W Equilibrium 
Step 1. CALCULATE H-W.
Step 2. COMPARE to our OBSERVED.
Step 3. Has an ASSUMPTION been VIOLATED?
Step 4. Use your analysis to set up the ALTERNATIVE HYPOTHESIS.

Question 34

What is the purpose of the Chi^2 Test?

Answer 34

It compares the OBSERVED data to the EXPECTED (h-w) data.

Question 35

[Chi^2 and H-W] When do we REJECT the null hypothesis?

Answer 35

Chi > H-W

When Chi is LARGER than H-W, the population is NOT IN EQUILIBRIUM.

Question 36

[Chi^2 and H-W] When do we FAIL TO REJECT the null hypothesis?

Answer 36

Chi < H-W

When Chi is SMALLER than H-W, the population IS in equilibrium.