Autosomal vs Mitochondrial DNA
Definition
Autosomal DNA is nuclear, biparentally inherited, present as two copies per cell. Mitochondrial DNA is cytoplasmic, maternally inherited, present in hundreds to thousands of copies per cell.
- Autosomal DNA
- Nuclear, biparental, 2 copies per cell
- Mitochondrial DNA
- Cytoplasmic, maternal, hundreds to thousands of copies per cell
- Autosomal use
- Individual identification via STR profiling
- mtDNA use
- Degraded samples and maternal lineage tracing
Common questions
Why is mitochondrial DNA preferred for badly degraded or old skeletal samples?+
Its much higher copy number per cell improves the odds of successful recovery when nuclear DNA has broken down too far to yield a usable autosomal profile, even though it is less individually discriminating.
Can mitochondrial DNA distinguish between maternal siblings?+
No. Full siblings sharing the same mother, and other relatives along the maternal line, carry an identical mitochondrial sequence, so mtDNA alone cannot tell them apart.
Related terms
- Capillary Electrophoresis
- Size separation of fluorescently labelled PCR products through a polymer-filled capillary on an instrument like the ABI 3500. Output is an electropherogram.
- Chromosome
- A discrete, condensed structure consisting of a single long DNA molecule complexed with histone proteins. Humans normally carry 46 chromosomes in 23...
- CODIS
- The FBI's Combined DNA Index System, the US national STR-based forensic DNA database. Contains profiles from convicted offenders, arrestees, and unidentified crime-scene...
- Multiplex STR Kit
- Single-tube PCR amplifying 15+ STR loci plus amelogenin in one reaction. AmpFISTR Identifiler Plus and PowerPlex are the workhorses in Indian DNA...
- Nucleotide
- The monomer unit of nucleic acids. Each nucleotide consists of a five-carbon sugar (deoxyribose in DNA, ribose in RNA), a phosphate group,...
- PCR
- Polymerase Chain Reaction. Kary Mullis 1983. Exponential amplification of a target sequence using a thermostable Taq polymerase, two primers and thermal cycling.
- RFLP
- Restriction Fragment Length Polymorphism. The first-generation DNA typing method using restriction enzymes and Southern blotting. Required nanograms of intact DNA.
- SNP (Single Nucleotide Polymorphism)
- A position in the genome where the nucleotide base differs between individuals. Genome-wide SNP panels are more powerful than STR panels for...
- STR (Short Tandem Repeat)
- A genomic locus where a 2, 7 base-pair unit is repeated in tandem a variable number of times between individuals. The variation...
- VNTR
- Variable Number Tandem Repeats. Longer repeat units (10 to 100 bp) than STRs. The original Alec Jeffreys 1984 fingerprinting markers, now superseded...
- Watson-Crick Base Pairing
- Adenine pairs with thymine via two hydrogen bonds; guanine pairs with cytosine via three. The pairing rule that makes the double helix...