EE Lecture 3: Genetic Variation Flashcards
what is the source of variation
mutation
recombination
who discovered the structure of DNA
rosalind franklin
watson and crick
mauric wilkins
what are nucleotides
units of DNA/RNA composed of sugar, a phosphate and one of five bases
which nucleotides are purines
adenine and guanine
which nucleotides are pyrimidines
thymine
cytosine uracil
which of nucleotides are one ring molecules
pyrimidines
which nucleotides are two ring molecules
purines
what is an SNP
single nucleotide polymorphism
change from one base
what is an INDEL
insertion or deletion event
what is a synonymous substitution
one that doesnt change amino acid sequence
what is a non synonymous substitution
one that does change amino acid sequence
give an example of the effect of mutations on proteins (1)
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
give an example of the effect of mutations on proteins (2)
DMD duchenne muscular dystrophy caused by premature stop codon for dystrophin located on X codon
where is dystrophin gene located
X chromosome
what does a premature stop codon for dystrophin cause
duchene muscular dystrophy
how is duchene muscular dystrophy caused
premature stop codon on dystrophin gene on X chromosome
what are symptoms of Duchene Muscular Dystrophy
how many affected
severe muscle wasting and
death
effects 1 in every 3500 males
how is SCA cause (sickle cell anaemia)
base sub of A to T in DNA sequence coding for Hb
causes aa change from glu to val
what is aa sequence change that causes SCA
glu to val
what is an STR mutation
Short Tandem Repeat
name some DNA functional regions
promoter regions
RNA genes
give an example of a frameshift mutation
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
what is a Delta 32 mutation
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
which transmembrane protein does HIV1 require to gain entry into cells
CCR5
what is CCR5
a transmembrane protein -chemokine receptor type 5 which HIV1 requires to gain entry into cells
what is the result of being a CCR5Delta32 homozygoe
HIV1 resistant - as HIV requires CCr5 to gain entry into cells
what is the neutral theory of molecular evoln
evoln occured at similar rates in phylogenies
observed genetic variation is greater than predicted by natural selection
is observed genetic variation lesser or greater than predicted by natural selection
observed genetic variation is greater than predicted by natural selection
what is mutation rate
µ
how many mutations are there per site per generation
2Neµ
what is the probability that a new mutation will be fixed
1 / 2Ne
what is the equation for substitution rate
µ = 2Neµ x (1/2Ne)
what is word eqtn for substitution rate
mutations per site per generation * probability new mutation is fixed
at what rate does neutral evoln occur in large and small pops for a given µ
natural evoln occurs at the same rate in large and small pops for a given µ
which produces more mutations and fixes more mutations, small pops or larger pops
smaller pops produce fewer mutations but fix a higher proportion
which takes longer to fix mutations, smaller or larger populations
larger populations take longer to fix mutations
which can hold more variation, smaller or larger pops
larger pops can hold more variation
when is mutation drift eqbm reached
when new mutations balance diversity lost to drift`
what is reached when new mutations balance diversity lost to drift
mutation drift eqbm
what are most mutations
selectively neutral
what is neutral genetic variation a function of
popn size
