- 01 Introduction
- 02 Biology of DNA
- 03 Practical Issues Specific to DNA Evidence
- 04 Introduction to the Forensic DNA Laboratory
- 05 Assuring Quality in DNA Testing
- 06 Understanding a Forensic DNA Lab Report
- 07 Statistics and Population Genetics
- 08 Mitochondrial DNA & Y-STR Analysis
- 09 Forensic DNA Databases
- 10 Collection of DNA Evidence from Suspects and Arrestees
- 11 Pretrial DNA Evidence Issues
- 12 Victim Issues
- 13 Trial Presentation
- 14 Postconviction DNA Cases
- 15 Emerging Trends
Principles of Forensic DNA
for Officers of the Court
for Officers of the Court
Module 8 :: mtDNA & Y-STR
Topic 3 :: mtDNA Considerations
Sequence (Site) Heteroplasmy
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.
