BIO5: Genetic Analyses, Evolution, and Natural Selection

Question 1

Dihybrid cross

Answer 1

Parent x parent –> F1 generation (x F1) –> F2 generation

Question 2

Autosomal recessive disorders

Answer 2

All affected indiviudals have 2 carrier parents

Question 3

Autosomal dominant disorders

Answer 3

All affected individuals have 1 affected parent (appears every generation)

Question 4

In order to do a pedigree

Answer 4

The disorder must exhibit dominance and must not be sex-linked

Question 5

Testcross

Answer 5

Used to determine if an individual that shows the dominant phenotype is homozygous (AA) or heterozygous (Aa) by crossing the individual with a homozygous recessive individual

Question 6

Backcross

Answer 6

Hybrid individual crossed with one of the parent to determine recombination (ie. How far a part genes are)

Question 7

How do you calculate Rf from a backcross?

Answer 7

Rf= sum of % of recombinants in backcross progeny

Question 8

Epistasis

Answer 8

The expression of alleles for 1 gene is dependent on the alleles for another gene (e.g. pigment gene vs color gene)

Question 9

Pleiotropy

Answer 9

1 gene that affects multiple different traits (e.g. PKU)

Question 10

Allelic series

Answer 10

Multiple different alleles for a gene with varying degrees of dominance (e.g. blood type IA=IB>i

Question 11

Complementation test

Answer 11

Used to determin whether two individuals with the same phenotype carry mutations on the same gene or different genes

Question 12

How is the complementation test performed?

Answer 12

Cross two homozygous individuals with similar mutant phenotypes (e.g. AAbb x aaBB) and see if complementation/WT phenotype (AaBb) occurs/if mutant alleles are on 2 different genes

Question 13

Polygenetic

Answer 13

Traits that are influenced by multiple different genes (genes interact additively to produce the phenotype - e.g. skin color)

Question 14

Expected phenotype ratio for two heterozygotes if completely dominant

Answer 14

3:01

Question 15

Expected phenotype ratio for two heterozygotes if codominant/incomplete

Answer 15

1:02:01

Question 16

Expected phenotype ratio for two double heterozygotes if complete dominance

Answer 16

9:3:3:1

Question 17

Expected phenotype ratio for two double heterozygotes if recessive epistasis

Answer 17

9:3:4 (aa for gene 1 is dominant over gene 2)

Question 18

Expected phenotype ratio for two double heterozygotes if dominant epistasis

Answer 18

12:3:1 (A for gene 1 is dominant over gene 2)

Question 19

Evolution

Answer 19

A change in heritable traits of a population across multiple generations

Question 20

What are the driving forces of evolution?

Answer 20

1. Natural selection
2. Random genetic drift
3. Mutation
4. Gene flow
5. Bottleneck effect

Question 21

Genetic drift

Answer 21

Sudden change in allele frequencies due to chance alone (ie. random sampling)

Question 22

Gene flow

Answer 22

The movement of genes between populations (ie. Migration)

Question 23

Bottleneck effect

Answer 23

Population size is dramatically reduced (ie. Disaster) and has nothing to do with fitness

Question 24

Convergent evolution

Answer 24

Different species without a common ancestor evolve similar traits due to adaptation to a similar environment (A/B -> S/S)

Question 25

Divergent evolution

Answer 25

Species with a common ancestor diverge away from each other over time (accumulate differences)

Question 26

Analogous structures

Answer 26

Similar traits (not due to common ancestry but environment) and serve a similar purpose (eg. Wings)

Question 27

Homologous structures

Answer 27

Structures that appear in different animals due to common ancestry but may be adapted for different purposes (eg. Phalanges)

Question 28

Hardy Weinberg Equilibirum

Answer 28

Allele frequencies in a gene pool will stay CONSTANT if: 1. No mutation 2. No migration 3. No natural selection 4. Random mating 5. Large population

Question 29

How does the hardy weinberg equilibirum relate to evolution?

Answer 29

If there are no changes in allele frequencies (HW equilibirum), there is no evolution (defined by changes in allele frequencies)

Question 30

Hardy Weinberg equation

Answer 30

For a single gene with two alleles: p+q=1 and p^2+2pq+q^2 = 1 (p^2 = freq. AA, q^2 = freq. aa, 2pq = freq. Aa)

Question 31

How do you determine if a population is in HW equilibirum?

Answer 31

Compare the allele frequencies across at least 2 generations. If they are the same, then the population is in HW equilibrium

Question 32

How do you calculate allele frequencies?

Answer 32

p (dominant allele) = AA + 1/2 Aa, q (recessive allele) = aa + 1/2 Aa

Question 33

What is the result of natural selection?

Answer 33

Alleles associated with advantageous traits becoming more abundant in subsequent generations

Question 34

Domain

Answer 34

Bacteria, archea, eukarya

Question 35

What are the differences between bacteria, archea, and eukarya

Answer 35

Bacteria and archaea are prokaryotes w/ no nuclei, eukarya includes all other animals, plants, fungi and single-celled protists

Question 36

What is unique about bacteria vs. archae and eukarya?

Answer 36

Contain peptidoglycan in the cell walls

Question 37

What is unique about eukarya vs. bacteria?

Answer 37

Eukarya cell walls do not contain peptidoglycan

Question 38

Kingdom

Answer 38

Protists,fungi, plantae, animalia

Question 39

Order of phylogeny

Answer 39

Domain, kingdom, phylum, class, order, family, genus, species (dumb kids playing chase on the freeway get squished)

Question 40

Protists

Answer 40

Simple, unicellular eukaryotic organisms (e.g. slime molds, algae, protozoans)

Question 41

What kingdom are yeasts from?

Answer 41

Fungi

Question 42

Species

Answer 42

Group of genetically similar organisms that are able to interbreed, producing viable and fertile offspring

Question 43

Population

Answer 43

Group of organisms of the same species that live in the same general region and naturally interbreed with each other

Question 44

Types of symbioses

Answer 44

1. Mutualism (++) 2. Commensalism (+0) 3. Parasitism (+-)

Question 45

Symbiosis

Answer 45

2 organisms interacting closely

Question 46

Speciation

Answer 46

Creation of new species

Question 47

Why does speciation generally occur?

Answer 47

Organism enters a new niche or a geographical barrier is removed