Forensic mitochondrial DNA analysis

Article By:

Melton, Terry Mitotyping Technologies, State College, Pennsylvania.

Last reviewed:2003

DOI:https://doi.org/10.1036/1097-8542.YB030170

Deoxyribonucleic acid (DNA) is found in two locations in all human cells, except in red blood cells. Nuclear DNA (nuDNA), inherited from both parents, makes up 23 pairs of chromosomes in the nucleus of somatic cells. Mitochondrial DNA (mtDNA), inherited only from the mother, is located in the mitochondria, the peanut-shaped cytoplasmic organelles that generate cellular energy. The coding region of mtDNA contains 37 genes encoding proteins involved in cellular respiration, transfer ribonucleic acid (RNA), and ribosomal RNA. The full complement of nuDNA has about 3 billion of the four chemical bases of DNA (adenine, guanine, thymine, and cytosine, abbreviated A, G, T, and C; also known as nucleotides), in a linear array within the chromosomes. Mitochondrial DNA contains 16,569 of these same chemical bases within a circular molecule (Fig. 1). Whereas each cell contains two copies of nuDNA, there are hundreds to thousands of mtDNA molecules within dozens to hundreds of mitochondria per cell, depending on the particular tissue. With some exceptions, all tissues in an individual are homogeneous for a single mtDNA type.

The content above is only an excerpt.