Lecture 8: Mitochondrial DNA (unfinished ) Flashcards
what DNA markers are shuffled with each generation?
Autosomal
Lineage Markers are passed on how ?
passed down generations
mitochondrial DNA is inherited from?
mum
mitochondrial DNA stay stem same for who?
child, mother, grandmother etc. only mutations cause changes
does everyone have mitochondrial DNA?
yes
Lineage markers are not as great at identifying people as what?
nuclear DNA
where is majority of Human DNA located?
in the nucleus
when can it be hard to obtain nuclear DNA?
Ancient DNA
Badly degraded
Bone, teeth, hair
if theres no direct relatives to act as refrences, what used instead of nuclear DNA?
mitochondrial
where is mitochondria found?
cells cytoplasm
what does mitochondria contain?
several strands and loops of mitochondrial DNA - can contain 1000’s of copies of DNA
Mitochondrial DNA has a ___ copy rate.
high
Mitochondrial main
responsibility is what?
Responsible for energy production – 90% of the energy required by the cell
mitochondria converts what?
Convert food energy -> Adenosine Triphosphate (ATP)
in every mitochondria how many copies of DNA is there?
1-15 copies mtDNA per mitochondria (average 4-5)
why is mitochondria DNA used for degraded samples?
because of the high copy number of mtDNA
mtDNA survives traumatic experiences and in ancient tissues because what?
It has 2 cell walls ,resistant to nucleases which degrade DNA
mtDNA can be tracked over generations because?
No recombination
whats the shape of mtDNA?
Circular DNA molecule ( not helix )its a loop
is mtDNA double stranded?
yes
what are the two strands of mtDNa?
Heavy strand = purine-rich (A/G)
Light strand = pyrimidine rich (C/T)
mt DNA has how many base pairs? how many genes does it code for?
16,569 , codes for 37 genes
what’s the control region in the mtDNA?
Displacement loop (d-loop)
mtDNA is separated at which part?
at the d-loop
nucDNA and mtDNA which one mutates faster?
mtDNA mutation rate is 10x greater than for nucDNA
what 2 main regions of mtDNA do we go to every time?
Hypervariable region 1 and Hypervariable region 2
where are the Hypervariable regions located?
within the d-loop
why does mtDNA mutate rapidly?
- Fewer DNA repair mechanisms
- a lack of proof-reading capabilities in the mtDNA polymerase
- replicates frequently
- vulnerable to cumulative damage from free radicals generated by the electron transport chain
the d loop is a what region?
a non coding region
where do mutations happen in mt DNA?
in the d-loop
do the mutation sin mtDNA affect cell function?
no
the d-loop does not?
code for nay gene product s
why does mtDNA not come form dads?
sperm mid-piece contains around 50-75 mitochondria, small amount
how much mtDNA does the egg contain compared to sperm?
mtDNA copy number in the egg exceeds that in the sperm by at least a factor of 1000
what happens to the sperms mtDNA?
When the sperm penetrates the egg it is thought that the paternal mtDNA is either actively removed (no evidence), or diluted beyond recognition
mtDNA is referred to as what?
a haplotype
what does a haplotype mean?
only one copy of the genome
How are Haplogroups useful?
- tracking migration
- can show geographical clustering
mtDNA vs nucelar DNA, what are the differences?
- 3.2 billion bp fo rnucDNA vs 16569 for mtDNA
- mtDNA more copies , Nuclear DNA 2 copies
- NucDNA linear structure, mtDNA circular structuren
- mtDNA form mum nut from both
- nuc DNA unique to individual mtDNA not
what percent is mtDNA fo rate total cell DNA?
0.25%
how many variable regions ar ether within the d-loop?
3 regions
how long id the d loop in terms of bp?
It is ~1100bp long
HV I and HV II are found in the ?
control region. no personal info.
HV I and HV II have the feastest rate of?
mutation, good for tracking
Bases 16024-16365 covers ?
HVR1
HVR2 covers what bases?
73-340
when is HVR3 used?
when we are struggling with using the other areas
what can cause differences in mtDNA?
- substitutions
- insertions
- deletions
stoped at slide
17 pb 1:15
