Molecular Evolution

Question 1

What does the theory of “On the Origin of Species “ explain?

Answer 1

It explain the current variety of life on earth

Question 2

What are the 2 main concepts the charles darwins theory?

Answer 2

Natural selection and Fitness

Question 3

What is natural selection?

Answer 3

The effects of a wide range of factors on the frequency of heritable changes in a species

Question 4

What is fitness?

Answer 4

How well a species is able to reproduce in an environment

Question 5

what happens if the fitness increase ?

Answer 5

This change will be selected for

Question 6

What happens if the fitness decreases?

Answer 6

The change will be selected against

Question 7

What is the Modern Synthesis?

Answer 7

Genetics alongside evolution can be unifies to explain the molecular processes underlying evolution

Question 8

What is the main source of heritable changes in a species?

Answer 8

Genetic Variation

Question 9

What effects the frequencies of genetic variants? ( 4 in total)

Answer 9

Selection
Mutation
Migration
Genetic Drift

Question 10

What is Selection?

Answer 10

Selection is where genetic variants display a positive advantage that will be selected for and passed on to further generations

Question 11

Give examples of Selection

Answer 11

• resistance to a disease
• ability to metabolise a new food source
• antibiotic resistance
• changes in appearance that enhances mating choice

Question 12

In terms of the genome, what does it mean to be conserved?

Answer 12

Parts of the genome that are resistant to change

Question 13

Why are some parts of the genome conserved?

Answer 13

They are conserved as they contain vital sequences and are essential for the organisms survival

Question 14

What is Mutation?

Answer 14

The name of the process that allows variation to arise in the genome

Question 15

What does the number of mutations depend on?

Answer 15

It depends on the selection and when the first mutation arose

Question 16

How may a variant be rare?

Answer 16

It may be rare if it recently arose or if it is deleterious

or both!

Question 17

What is Migration?

Answer 17

Physical movement of people form a different population resulting in new pools of variant being introduced to the existing population

Question 18

What is another term used for migration ?

Answer 18

Admixture

Question 19

A population frequency may change due to what?

Answer 19

It can change due to Admixture

not just due to disease

Question 20

What is Genetic Drift?

Answer 20

How the frequency of a variant changes in a population due to chance

Question 21

What mechanism will result in not all genetic variants being passed on?

Answer 21

Recombination

Question 22

True or False

Will all organisms pass on all their genetic variants

Answer 22

FALSE

• not all organisms will pass on their genetic variants
• all variants are subject to genetic drift

Question 23

What type of sequences don’t show evidence of variation?

Answer 23

DNA sequences that are vital to the survival of the organism

Question 24

What happens if there is variation in conserved regions? and why?

Answer 24

they are usually selected against as they are likely to have deleterious effects

Question 25

Which regions have high conservation ?

Answer 25

Coding regions | Not exons - as these contain non -coding regions

Question 26

Which regions have intermediate conservation?

Answer 26

Promoter 5' UTR 3' UTR Terminator

Question 27

Which regions have low conservation?

Answer 27

Introns 3rd Base of codons terminator

Question 28

Why is there flexibility in variation of the 3rd base of a codon?

Answer 28

Due to some amino acids having multiple codons coding for it

Question 29

What can a cross species comparison be used for?

Answer 29

Used to generate an evolutionary profile for a gene or a gene family

Question 30

Give an example of a conservation gene

Answer 30

NAMPT | Nicotinamide Phosphoribosyltransferase

Question 31

What are Phylogenetics?

Answer 31

Phylogenetics is the study of the history of our genome

Question 32

What is the pattern for studying phylogenetics

Answer 32

1. observe sequences 2. reconstruct evolutionary histories 3. learn more about evolutionary processes 4. develop better evolutionary models 5. repeat

Question 33

What is the main aim of a phylogenetic tree?

Answer 33

To illustrate the relatedness of different species

Question 34

What does distance on a phylogenetic tree mean?

Answer 34

Distance between two entities shows how similar they are

Question 35

What is the distance on the tree due to?

Answer 35

Distance is due to evolutionary pressures and times

Question 36

How is time estimated?

Answer 36

Time is estimated by mutation rates

Question 37

What is the theory of how HIV was introduced?

Answer 37

HIV was introduced via a contaminated polio vaccine

Question 38

How did the polio vaccine come to be contaminated?

Answer 38

Polio vaccines were made via cultured chimpanzee cells which may been infected with SIV

Question 39

What is Gene duplication?

Answer 39

The duplication of a DNA sequence containing a gene

Question 40

What is the mechanism behind Gene Duplication?

Answer 40

The unequal crossing over during meiosis

Question 41

What happens to the copies after duplication?

Answer 41

- One copy will continue with the original function | - The other copy can evolve to have a new function due to changed in the coding sequence

Question 42

What are the two clusters of Globin genes?

Answer 42

1. Alpha like | 2. Beta like

Question 43

Which chromosome is Alpha like globin genes found on? what type of genes make up this cluster?

Answer 43

Chromosome 16 | 4 genes and 3 pseudogenes

Question 44

Which chromosome is Beta like globin genes found on? What type of genes make up this cluster?

Answer 44

Chromosome 11 | 5 genes and 1 pseudogene

Question 45

Through what mechanisms have globin genes evolved from?

Answer 45

Through duplication and accumulation of mutations (divergence)

Question 46

What are pseudogenes?

Answer 46

Non functioning genes

Question 47

What does divergence of promoter allow?

Answer 47

Allows different transcription factors to bind meaning the expression of genes at different stages of development eg. embryo -> foetus -> postnatal

Question 48

TRUE OR FALSE pseudogenes have many mutations and are non functional

Answer 48

True there are many pseudogenes in our genome

Question 49

What processes do pseudogenes complicate?

Answer 49

PCR and sequencing

Question 50

What causes sickle cell disease?

Answer 50

Single nucleotide mutation

Question 51

When do symptoms of SCD usually show?

Answer 51

5-6 months of age

Question 52

What are the main symptoms?

Answer 52

- Anaemia : fatigue, restlessness, jaundice - Acute Pain Episode : due to o2 deprivation in tissues - Increase frequency of infections : spleen damage

Question 53

Where does the single base change occur for SCD?

Answer 53

In the Beta Globin gene of Haemoglobin A

Question 54

What is the new mutated Haemoglobin known as?

Answer 54

Haemoglobin S (HbS)

Question 55

What is the codon change for SCD?

Answer 55

GAG to GTG

Question 56

The codon changes what amino acid in to what? at what position?

Answer 56

Glu to Val at position 7

Question 57

What type of disease is SCD?

Answer 57

Autosomal Recessive disease

Question 58

What is the effect of having two copies of the HbS variant?

Answer 58

It has a negative effect on reproductive ability

Question 59

What is the effect of only having one copy of the HbS variant?

Answer 59

Resistant to Malaria

Question 60

What is meant by 'Heterozygous Adavantage'

Answer 60

It means the HbS variant is maintained in the population when otherwise it would have been selected against and lost

Question 61

When did the SCD mutation arise?

Answer 61

approx. 7300 years ago