DNA
sequences
STRs
STRs & individuals
Electrophoresis
DNA length
STR patterns
PCR
Sources
Mitochondrial
DNA
Mitochondrial
patterns
Mitochondrial DNA is maternally inherited. That means that all of a woman's children have the same mitochondrial DNA as she does. Unlike the majority of cellular DNA, mitochondrial DNA is not a blend of the mother and father; you do not inherit any of your father's mitochondrial DNA. Brothers and sisters have the same mitochondrial DNA. So, unlike STRs, individuals do not have unique mitochondrial DNA.
Mitochondrial DNA is not as good as STR analysis in identifying individuals, because there are not as many forms of mitochondrial DNA patterns, but it is useful in determining family relationships.
In this family tree squares represent males and circles represent females. The mitochondrial DNA alleles are color-coded.
In the first generation, the grandmother has the green allele and the grandfather has the red allele. All their sons and daughters have the green allele, like their mother.
In the second generation, the daughters pass on their green allele to all their children. One son marries a woman with the orange allele, and their children also have the orange allele.
The second family tree below also shows males as squares and females as circles. Some of the family members don't have their mitochondrial DNA allele shown (white circles or squares). Can you match the family member to the mitochondrial DNA allele?
