Evolution Test 2

Front 1

What are the "molecules of evolution?"

Back 1

RNA, DNA, Proteins

Front 2

Describe Proteins and their functions

Back 2

-Amino Acid Polymers
-Functions: enzymes, structural, binding, transport, signaling, repair/growth

Front 3

DNA

Back 3

-Double-stranded polymer of A, G, T, C
-Phosphodiester bonds & hydrogen bonds
-Expressed phenotypically as RNA/PROTEIN

Front 4

What are mutations?

Back 4

-Random changes of DNA that occur during replication/transcription
-May manifest as a phenotypic change
-May alter structure/function

-Heritable mutations are the basis of evolution; inevitable over DEEP TIME

Front 5

RNA

Back 5

-Single-stranded polymer of A, U, G, C
-A temporary secondary copy of the "master" DNA
-Used for translation to make protein

Front 6

Define: GENE

Back 6

Sequence of nucleotides with a particular function

-Codes for protein or RNA
-Regulates other genes

Front 7

Central Dogma of Molec. Biology

Back 7

DNA TRANSCRIPTION CREATES RNA, which is PROCESSED into MATURE RNA with the addition of a POLY A TAIL, a 5’ CAP, and the SPLICING out of INTRONS, This MATURE RNA is then TRANSLATED into a PROTEIN

Front 8

Genetic Expression is regulated by what?
Describe each.

Back 8

• Histone Winding – Condensing of DNA over histone proteins
o Methylation: Tightens DNA and makes DNA inaccessible
o Acetylation: Loosens and exposes DNA  Makes DNA accessible

Transcription factors (repressors, activators) and Hormones:
o Bind to some places on DNA and effect expression

Alternative Splicing:
o Introns are cut out and exons are lost or kept  Resulting in different final proteins

Post-Translational Processing:
In the Smooooth ER, protein is further modified  See book examples

Front 9

What does a genome include?

Back 9

All the DNA, RNA of an organism

-And rRNA , micro RNA
-Pseudogenes: Genes no longer expressed
-Mobile Genetic Elements: Sets of nucleotides that duplicate and reinsert themselves (like viruses)

--These all affect genome size and complexity

Front 10

What's a pseudogene?

Back 10

A gene no longer expressed, but still part of the genome ... (old DNA/RNA)

Front 11

What are mobile genetic elements (MGEs)?

Back 11

Sets of nucleotides that duplicate and reinsert themselves (self-replicating) similar to a virus (did they originate from viruses?)

Front 12

What do mobile genetic elements have to do with evolution?

Back 12

-May lead to disease, cancer
-May lead to positive or negative adaptations
-Can affect host and neighboring bacteria
-Changes are VERY fast

Front 13

What are some sources of evolution?

Back 13

-Ionizing radiation (thymine dimerization)

-environmental chemicals

-DNA replication and transcription errors

Front 14

What types of mutation are there?

Back 14

-Point Mutation
-Insertion/Deletion Mutation
-Gene Duplication
-Gene Inversion
-Chromosome Fusion
-Aneuploidy

Front 15

What are the types of point mutations?

Back 15

Silent (same AAs)
Mis-Sense (wrong AAs)
Non-Sense (STOP CODON)

Front 16

Why can insertions and deletions cause a massive change?

Back 16

Frame shift changes can be extreme!

Front 17

What determines whether a mutation is beneficial or harmful?

Back 17

SELECTION

Front 18

What are CIS-ACTING ELEMENTS?

Back 18

Series of nucleotides in a gene that affect amount, timing, and location of a gene

Front 19

What are TRANS-ACTING ELEMENTS?

Back 19

Exogenous transcription factors (outside the gene)

--GENES ARE AFFECTED BY DISTANT MUTATIONS

Front 20

Examples of SINGLE AA-CHANGE Diseases?

Back 20

Albinism
Syndactyly
Muscular Ossification Disease

Front 21

Examples of SINGLE NUCLEOTIDE CHANGES?

Back 21

Polydactyly, Progeria

Front 22

How does location of a mutation matter?

Back 22

Somatic cells -- Affects only one generation, may or may not be fatal

Germ-Line Cells -- Can affect many, may be heritable

Front 23

How does variation occur in ASEX reproduction?

Back 23

-Point Mutations
-Plasmid Transfer
-Parthenogenesis
-Fission
-Budding

Front 24

How does variation occur during SEX reproduction?

Back 24

Meiosis -- Crossing over of chromosome tails
Sister chromatids' reassortment

Front 25

Genetic Polymorphism

Back 25

Two or more discrete variations of an allele exist within a population

Front 26

Mendelian Genetic's Polymorphism

Back 26

Different phenotypes expressed by a single locus on the genotype... One dominant, one recessive

Front 27

Epistasis

Back 27

One gene controls expression of another

Front 28

Incomplete Dominance

Back 28

Neither allele is expressed completely

Front 29

Co-Dominance

Back 29

Both alleles expressed at once

Front 30

Pleiotropy

Back 30

One gene has many effects

Front 31

Polygenic Inheritance

Back 31

Many genes have just one effect (height, weight)

Front 32

How does pleiotropy affect evolution?

Back 32

Most likely constrains evolution... Survival due to changes will be based on cost/benefit ratio

Front 33

HOW IS PINK BOLLWORM AN EXAMPLE OF PLEIOTROPY

Back 33

Bt toxin injected into plants, so that pink bollworm insect is killed... HOWEVER, insects that are resistant to Bt toxin are also less resistant to gossypol toxin

Front 34

HOW IS D. discoideum AN EXAMPLE OF PLEIOTROPY

Back 34

Only sporulating body passes on genes to next generation... DimA Gene for stalk/spores is present ONLY in cells that can sporulate

No gene = no sporulation

Front 35

HOW IS CERVICAL VERTEBRA IN MAMMALS PLEIOTROPY?

Back 35

Gene for seven vertebra is related to metabolic mechanisms... Different number increases likelihood of cancer... Sloth and manatees are exceptions, but they are both very slow!

Front 36

Example of Polyphenism:

Back 36

Insect Morphs
-horn length varies greatly due to nutritional cues
-social hierarchy in insects

Front 37

What is discreet varying of genes?

Back 37

Polymorphism, Polyphenism
Only tell the difference by looking at the phenotype

Front 38

What is continuous varying of genes?

Back 38

Quantitatively measureable
Obvious genetic difference to DNA

Front 39

Examples of external environmental impacts on phenotype

Back 39

• Oxygen Availibility – Rate of respiration/ATP Supply
• Nutrition
• Temperature – Rate of reactions
• Stress… Mechanism?
Both hormonal and cellular
• Unwinding of histones affects growth, metabolism, behavior

Front 40

Examples of internal influences on phenotype

Back 40

Changes in ECF (morphogens) or ICF (blastulation; the cut into 8 cells creates polarity)

Front 41

What is phenotypic plasticity?

Back 41

Phenotype will vary in expression due to environment

Front 42

Mosquito Control In Italy

Back 42

-Use of Organophosphates -- Inhibit AChE
(causes ACh to never stop, all ATP wasted)
Mosquitos come back after 3 years
Survivors have ESTER1 gene
3 more years and almost all have resistance

Front 43

Population Genetics

Back 43

Study of allele distribution in a population over time

Front 44

Genotype

Back 44

all alleles at a specific locus

Front 45

Gene Pool

Back 45

All alleles, at all loci, within a population

Front 46

Hardy Weinberg Theorum

Back 46

A gene pool remains constant over time unless acted up by some process

Front 47

Assumptions of Hardy Weinberg Theorum:

Back 47

Large population (no genetic drift or bottlenecking)
All genotypes survive equally
No net migration of alleles
No mutations

NOTE: NOT TRUE FOR ANY REAL POPULATIONS

Front 48

What processes prevent HARDY WEINBERG?

Back 48

Genetic drift affects all populations -- all randomness is lost over time

Natural selection -- environmental factors favors survival of alleles unequally

Migration -- Individuals may enter/leave a population

Mutations -- alleles change randomly over time

Front 49

Drosophila Experiment

Back 49

start with 107 drosophila
each population is 8 males, 8 females
each produces 16 progeny
this is repeated 19 generations

Result: genetic drift causes loss of alleles, all become either all red or all white

Front 50

Genetic Drift

Back 50

Change in allele frequency due to random chance, wheras selection is not random

Front 51

Ronald Fisher

Back 51

Supposed Natural Selection was most important of all evolutionary mechanisms

Front 52

Sewall Wright

Back 52

Believed genetic drift was the primary changer of allelic frequencies within a population

Front 53

Motoo Kimura

Back 53

Presented molecular data to prove importance of genetic drift

Front 54

Genetic Bottleneck

Back 54

Only a fraction of original population can pass on genes to the next generation

Front 55

Real life example of genetic bottleneck

Back 55

Northern Elephant Seal
-slaughetered by humans in 1800s
-thought extinct in 1900
-now approx. 120,000

-only 2 phenotypes in mtDNA (from 30)
-gene pool drastically reduced

Front 56

Founder effect

Back 56

Loss of genetic variation when a few members leave to form a new colony population

Front 57

Real life example of founder effect

Back 57

Afrikaner Population of south africa

-high prevalence of huntinton's disease

Front 58

Fitness

Back 58

Differential reproductive success; ability to produce offspring

Front 59

w = ?

Back 59

w = measure of fitness

Front 60

Average fitness?

Back 60

fitness of a whole population

Front 61

Relative fitness

Back 61

fitness of individual

Front 62

average fitness = 1
then...

Back 62

relative fitness is either greater or less than 1

Front 63

highest fitness in a population is 1...
then...

Back 63

average fitness must be less than one

Front 64

equation from class

Back 64

∆p = p x (aA1 / ̅ w ̅ )

Front 65

delta p = ?

Back 65

change in allele frequency due to selection

Front 66

p = ?

Back 66

frequency of a1 allele

Front 67

a(A1) = ?

Back 67

average excess of fitness for A1 allele

Front 68

( ̅ w ̅ ) = ?

Back 68

Average fitness of population

Front 69

If aA1 is positive...

Back 69

delta p will be positive

Front 70

If aA1 is negative...

Back 70

delta p will be negative

Front 71

Do silent mutations affect fitness?

Back 71

NO

Front 72

Do NONSENSE mutations affect fitness?

Back 72

YES, ALMOST ALWAYS

Front 73

Lenski Study 1 - Causing evolution through selection

Back 73

12 identical E. coli lines, only enough food for one day... after 500 generations they are frozen...

Selected for ability to survive no food!

Front 74

Lenski Study Part 2 - The Big Change

Back 74

Transformed ancestors with descendant DNA
Sequenced the transformed and untransformed DNA

Mutations had occurred in the BoxG1 gene-- responsible for cell wall integrity

Cell wall unimportant when survival is critical!

Front 75

Example of Pleiotropy Affecting Selection and vice-versa

Back 75

Mosquito Ester1 Gene
Confers resistance, but also susceptibility to predators
Ester 4 gene is now taking over

Front 76

Explain Selection acting on Dominant Vs. Recessive alleles

Back 76

Phenotype is always selected for...
Heterozygous recessive is more immune to selection, will eventually disappear due to genetic drift

Front 77

Example of Frequency-Dependent Selection

Back 77

Purple vs. Yellow Elderflowers -- Bees more likely to visit (And thus propogate) the less popular

Front 78

Selection on hetero/homozygous genes (balancing selection)

Back 78

-When the heterozygote is more fit than the homozygotes

-Example: Sickle Cell Anemia... Area with malaria, heterozygosity is better fit

Front 79

Selection Vs. Drift...
Who will win?

Back 79

A good allele will not survive if the population is too small due to drift. Genetic drift affects genes of a small population much more than selection!

A good gene must be sustained long enough by a large population for it to actually become common and increase the average fitness!