EE Lecture 3: Genetic Variation

Question 1

what is the source of variation

Answer 1

mutation

recombination

Question 2

who discovered the structure of DNA

Answer 2

rosalind franklin
watson and crick
mauric wilkins

Question 3

what are nucleotides

Answer 3

units of DNA/RNA composed of sugar, a phosphate and one of five bases

Question 4

which nucleotides are purines

Answer 4

adenine and guanine

Question 5

which nucleotides are pyrimidines

Answer 5

thymine

cytosine uracil

Question 6

which of nucleotides are one ring molecules

Answer 6

pyrimidines

Question 7

which nucleotides are two ring molecules

Answer 7

purines

Question 8

what is an SNP

Answer 8

single nucleotide polymorphism

change from one base

Question 9

what is an INDEL

Answer 9

insertion or deletion event

Question 10

what is a synonymous substitution

Answer 10

one that doesnt change amino acid sequence

Question 11

what is a non synonymous substitution

Answer 11

one that does change amino acid sequence

Question 12

give an example of the effect of mutations on proteins (1)

Answer 12

sickle cell disease
glu to val, DNA sub from T to A
Hb:protein expressed n surface of RBC responsible for binding oxygen and carrying it to other tissues

Question 13

give an example of the effect of mutations on proteins (2)

Answer 13

DMD duchenne muscular dystrophy caused by premature stop codon for dystrophin located on X codon

Question 14

where is dystrophin gene located

Answer 14

X chromosome

Question 15

what does a premature stop codon for dystrophin cause

Answer 15

duchene muscular dystrophy

Question 16

how is duchene muscular dystrophy caused

Answer 16

premature stop codon on dystrophin gene on X chromosome

Question 17

what are symptoms of Duchene Muscular Dystrophy

how many affected

Answer 17

severe muscle wasting and
death
effects 1 in every 3500 males

Question 18

how is SCA cause (sickle cell anaemia)

Answer 18

base sub of A to T in DNA sequence coding for Hb

causes aa change from glu to val

Question 19

what is aa sequence change that causes SCA

Answer 19

glu to val

Question 20

what is an STR mutation

Answer 20

Short Tandem Repeat

Question 21

name some DNA functional regions

Answer 21

promoter regions

RNA genes

Question 22

give an example of a frameshift mutation

Answer 22

Delta 32 mutation - 32 base pair deletion which knocjs out CCR5 gene function
this means that CCR5-Delta 32 homozygotes are resistant to HIV infection as HIV-1 requires CCR5 to gain entry into cells

Question 23

what is a Delta 32 mutation

Answer 23

32 base pair deletion which knocks out CCR5 gene function - CCR5 Delta 32 homozygotes are resistant to HIV-1 as HIV1 requires CCR5 to gain entry into cells

Question 24

which transmembrane protein does HIV1 require to gain entry into cells

Answer 24

CCR5

Question 25

what is CCR5

Answer 25

a transmembrane protein -chemokine receptor type 5 which HIV1 requires to gain entry into cells

Question 26

what is the result of being a CCR5Delta32 homozygoe

Answer 26

HIV1 resistant - as HIV requires CCr5 to gain entry into cells

Question 27

what is the neutral theory of molecular evoln

Answer 27

evoln occured at similar rates in phylogenies | observed genetic variation is greater than predicted by natural selection

Question 28

is observed genetic variation lesser or greater than predicted by natural selection

Answer 28

observed genetic variation is greater than predicted by natural selection

Question 29

what is mutation rate

Answer 29

µ

Question 30

how many mutations are there per site per generation

Answer 30

2Neµ

Question 31

what is the probability that a new mutation will be fixed

Answer 31

1 / 2Ne

Question 32

what is the equation for substitution rate

Answer 32

µ = 2Neµ x (1/2Ne)

Question 33

what is word eqtn for substitution rate

Answer 33

mutations per site per generation * probability new mutation is fixed

Question 34

at what rate does neutral evoln occur in large and small pops for a given µ

Answer 34

natural evoln occurs at the same rate in large and small pops for a given µ

Question 35

which produces more mutations and fixes more mutations, small pops or larger pops

Answer 35

smaller pops produce fewer mutations but fix a higher proportion

Question 36

which takes longer to fix mutations, smaller or larger populations

Answer 36

larger populations take longer to fix mutations

Question 37

which can hold more variation, smaller or larger pops

Answer 37

larger pops can hold more variation

Question 38

when is mutation drift eqbm reached

Answer 38

when new mutations balance diversity lost to drift`

Question 39

what is reached when new mutations balance diversity lost to drift

Answer 39

mutation drift eqbm

Question 40

what are most mutations

Answer 40

selectively neutral

Question 41

what is neutral genetic variation a function of

Answer 41

popn size