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Genomics Semester 3 > Molecular Evolution > Flashcards

Molecular Evolution Flashcards

1
Q

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

A

It explain the current variety of life on earth

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2
Q

What are the 2 main concepts the charles darwins theory?

A

Natural selection and Fitness

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3
Q

What is natural selection?

A

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

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4
Q

What is fitness?

A

How well a species is able to reproduce in an environment

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5
Q

what happens if the fitness increase ?

A

This change will be selected for

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6
Q

What happens if the fitness decreases?

A

The change will be selected against

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7
Q

What is the Modern Synthesis?

A

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

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8
Q

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

A

Genetic Variation

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9
Q

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

A

Selection
Mutation
Migration
Genetic Drift

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10
Q

What is Selection?

A

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

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11
Q

Give examples of Selection

A
  • resistance to a disease
  • ability to metabolise a new food source
  • antibiotic resistance
  • changes in appearance that enhances mating choice
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12
Q

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

A

Parts of the genome that are resistant to change

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13
Q

Why are some parts of the genome conserved?

A

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

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14
Q

What is Mutation?

A

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

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15
Q

What does the number of mutations depend on?

A

It depends on the selection and when the first mutation arose

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16
Q

How may a variant be rare?

A

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

or both!

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17
Q

What is Migration?

A

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

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18
Q

What is another term used for migration ?

A

Admixture

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19
Q

A population frequency may change due to what?

A

It can change due to Admixture

not just due to disease

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20
Q

What is Genetic Drift?

A

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

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21
Q

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

A

Recombination

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22
Q

True or False

Will all organisms pass on all their genetic variants

A

FALSE

  • not all organisms will pass on their genetic variants
  • all variants are subject to genetic drift
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23
Q

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

A

DNA sequences that are vital to the survival of the organism

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24
Q

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

A

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

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25
Q

Which regions have high conservation ?

A

Coding regions

Not exons - as these contain non -coding regions

26
Q

Which regions have intermediate conservation?

A

Promoter
5’ UTR
3’ UTR
Terminator

27
Q

Which regions have low conservation?

A

Introns
3rd Base of codons
terminator

28
Q

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

A

Due to some amino acids having multiple codons coding for it

29
Q

What can a cross species comparison be used for?

A

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

30
Q

Give an example of a conservation gene

A

NAMPT

Nicotinamide Phosphoribosyltransferase

31
Q

What are Phylogenetics?

A

Phylogenetics is the study of the history of our genome

32
Q

What is the pattern for studying phylogenetics

A
  1. observe sequences
  2. reconstruct evolutionary histories
  3. learn more about evolutionary processes
  4. develop better evolutionary models
  5. repeat
33
Q

What is the main aim of a phylogenetic tree?

A

To illustrate the relatedness of different species

34
Q

What does distance on a phylogenetic tree mean?

A

Distance between two entities shows how similar they are

35
Q

What is the distance on the tree due to?

A

Distance is due to evolutionary pressures and times

36
Q

How is time estimated?

A

Time is estimated by mutation rates

37
Q

What is the theory of how HIV was introduced?

A

HIV was introduced via a contaminated polio vaccine

38
Q

How did the polio vaccine come to be contaminated?

A

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

39
Q

What is Gene duplication?

A

The duplication of a DNA sequence containing a gene

40
Q

What is the mechanism behind Gene Duplication?

A

The unequal crossing over during meiosis

41
Q

What happens to the copies after duplication?

A
  • 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

42
Q

What are the two clusters of Globin genes?

A
  1. Alpha like

2. Beta like

43
Q

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

A

Chromosome 16

4 genes and 3 pseudogenes

44
Q

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

A

Chromosome 11

5 genes and 1 pseudogene

45
Q

Through what mechanisms have globin genes evolved from?

A

Through duplication and accumulation of mutations (divergence)

46
Q

What are pseudogenes?

A

Non functioning genes

47
Q

What does divergence of promoter allow?

A

Allows different transcription factors to bind meaning the expression of genes at different stages of development

eg. embryo -> foetus -> postnatal

48
Q

TRUE OR FALSE

pseudogenes have many mutations and are non functional

A

True

there are many pseudogenes in our genome

49
Q

What processes do pseudogenes complicate?

A

PCR and sequencing

50
Q

What causes sickle cell disease?

A

Single nucleotide mutation

51
Q

When do symptoms of SCD usually show?

A

5-6 months of age

52
Q

What are the main symptoms?

A
  • Anaemia : fatigue, restlessness, jaundice
  • Acute Pain Episode : due to o2 deprivation in tissues
  • Increase frequency of infections : spleen damage
53
Q

Where does the single base change occur for SCD?

A

In the Beta Globin gene of Haemoglobin A

54
Q

What is the new mutated Haemoglobin known as?

A

Haemoglobin S (HbS)

55
Q

What is the codon change for SCD?

A

GAG to GTG

56
Q

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

A

Glu to Val at position 7

57
Q

What type of disease is SCD?

A

Autosomal Recessive disease

58
Q

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

A

It has a negative effect on reproductive ability

59
Q

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

A

Resistant to Malaria

60
Q

What is meant by ‘Heterozygous Adavantage’

A

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

61
Q

When did the SCD mutation arise?

A

approx. 7300 years ago

Genomics Semester 3 (4 decks)

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