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In forensic identification, the study of the extracted DNA from old human remains represents a precious help. Indeed, when bodies are kept in particular conditions (cold, dry, anoxic and sterile environment) some small fragments (about 2OO pairs of bases) can be extracted. Thanks to a great number of copies by cell, the mitochondrial DNA is often the only one still present in sufficient quantities to be analysed. However, most of the time, it is extracted in small quantities, partly degraded or chemically modified, or sometimes co-extracted with reactions inhibitors or even contaminated by exogenous DNA. Thus, its extraction and its study require specific precautions. Handling must be made in sterile conditions to avoid any contaminations. The steps of DNA extraction and purification are crucial, and the methods based on phenol-chloroform and on the linkage between the DNA and a silica matrix seem to be the most effective ways to obtain sufficient yields of analysable material.

International audience; In recent decades, mitochondrial DNA has been widely analyzed in cases of identification in forensic medicine, due to its own specific characters, its maternal inherited transmission and its high mutation rate. In this review, the analysis of mitochondrial DNA by automated sequencing and its application in the forensic and genetic fields are discussed- Guidelines on working practices and nomenclature have been reviewed and precautions against erroneous data are pointed out. Difficulties in identifying and interpreting heteroplasmy are also exarnined. Widespread, intensive sequencing of mitochondrial DNA leads to new discoveries on mitochondrial DNA, its genetics and variations, but demands being very careful with data and quality controls. Finally, new approaches in phylogenetic and effective strategies appear to improve results and interpretation of mitochondrial DNA for each genetic research field.