1. Mitochondrial DNA
Notes 13.3

2. DNA Nuclear DNA Mitochondrial DNA (mtDNA)
23 pairs of chromosomes in the nucleus in which each parent contributes the chromosomes
Mitochondrial DNA (mtDNA)
Located outside the nucleus and contains DNA only from the mother

3. Mitochondria
Organelles that break down glucose in the presence of oxygen in a process called cellular respiration

4. Advantages A single mitochondrion contains several loops of DNA
Hundreds of mitochondria in each cell
Can be used when nuclear DNA is degraded (fire) or only a small amount is present (hair shaft)
A reference sample can be obtained from any maternally related relative
More sensitive than nuclear DNA
Plays a key role in the ID of human remains

5. Disadvantages More time consuming, costly, and rigorous
Only used by a few public and private labs
FBI has imposed strict limitations on the cases for which mtDNA technology can be used

6. How is mtDNA different from nuclear DNA
mtDNA is circular or a loop
each loop contains approximately 37 genes
Two regions are highly variable in humans
Region I (HV1) and region II (HV2)
Base sequences from HV1 and HV2 are available by the FBI lab and the Armed Forces DNA Identification Lab

7. How is mtDNA different from nuclear DNA cont.
mtDNA contains 5,000 sequences
Permits an assessment of how common or rare an observed sequence is

8. Important Note
mtDNA does not approach STR in its discrimination power and is best reserved for samples for which nuclear DNA is not possible to attain

9. In-Class Assignment/Homework
Ch. 13 Critical Thinking