Nuclear DNA and
Mitochondrial DNA
Nuclear DNA
• Present in almost
every cell
• Combination from
both parents; 23
chromosomes from
each parent
Mitochondrial DNA
• Each cell contains
thousands of mt, each
containing copies of
its DNA
• Mt DNA is in larger
quantities in a cell
• Nuclear DNA is larger
in size
Mt DNA is 16,569 bases in length and
consists of 2 different regions
• Coding Region
– Produces 13
proteins, 22tRNAs,
2rRNAs needed for
cell respiration
– This region has
very little variability
– So everyone’s DNA
in this region will be
nearly the same
sequence of
TGCAs
DNA
Coding Region
RNA
Protein
Trait
Control Region
This region is highly variable within the human population
Consists of 2 subregions
HV1 = 342 bp
HV2 = 268
Mt DNA is inherited from mom
• Every sibling will
get their mt DNA
from their
mother
• Why?
• Egg contains 23
chromosomes and
cell cytoplasm which
contains thousands
of maternal mt
• Sperm contains 23
chromosomes with
very little cytoplasm
Zygote = Fertilized Egg
• When egg
and sperm
join only
female mt
survive and
are passed
onto to new
baby.
Maternal Inheritance Pattern with
Mt DNA
Mutations occur in the
control region of mt
DNA at a regular rate
and are passed onto
children by the mom.
• We can compare DNA from the controlling
region to other living humans
– See how related to you are to each other
• Compare to prehistoric remains of human
fossils
– Identify where you DNA originated
– Identify ancestral relationships between
modern populations
• Compare your highly variable regions to
other species
Mitochondrial Eve
• Oldest women who
would have donated
her mtDNA to every
ancestor in the
world
• Comparisons can
be made by how
many variations
exist between her
DNA and your DNA.
1. Isolate DNA from cheek cells
2. Complete a PCR reaction
– Produce millions of extra copies of HV1 on
the control region of mtDNA
3. Send amplified DNA away to be
sequenced (Identify the exact sequence
of TGCAs in HV1 in your mtDNA)
4. Compare your sequence ot classmates
and database of prehistoric DNA
• 1. Isolating DNA
2. Polymerase Chain Reaction
• PCR
PCR Animation
PCR Animation
3. Sequencing DNA
Identify the exact sequence of nitrogen
bases in HV1 region
Sequencing DNA
4. Making Comparisons
Using a database you will compare your mt
DNA with:
• your classmates
• prehistoric DNA taken from fossilized
human remains.
• other species