U.S. flag

An official website of the United States government, Department of Justice.

Principles of Forensic DNA for Officers of the Court

Sequence (Site) Heteroplasmy

Home  |  Glossary  |  Resources  |  Help  |  Contact Us  |  Course Map

illustration of different site heteroplasmy
National Institute of Justice (NIJ) (see reuse policy).

Sequence (site) heteroplasmy is the presence of mtDNA molecules that have different nucleotides at the same address. For example, an electropherogram from a heteroplasmic hair might show both T and C at position 16,093. In a blood sample from the same individual, position 16,093 could show T or C, or T and C. A failure to exclude would be scientifically supported if the blood had any of these three possibilities, because the blood and hair share a common base at every position, including the heteroplasmic position.

If T and C are present in both hair and blood, the failure to exclude is actually strengthened because the heteroplasmy is in both samples.

Back Forward