I do not get the mitochondrial DNA and how they trace people's generations by it. What makes it different from nuclear DNA, where is the mitochondrial DNA located in a cell, etc?

Guru???

Mitochondrial DNA (mtDNA) provides a valuable locus for forensic DNA typing in certain circumstances. The high number of nucleotide polymorphisms or sequence variants in the two hypervariable portions of the non-coding control region can allow discrimination among individuals and/or biological samples. The likelihood of recovering mtDNA in small or degraded biological samples is greater than for nuclear DNA because mtDNA molecules are present in hundreds to thousands of copies per cell compared to the nuclear complement of two copies per cell. Therefore, muscle, bone, hair, skin, blood and other body fluids, even if degraded by environmental insult or time, may provide enough material for typing the mtDNA locus. In addition, mtDNA is inherited from the mother only, so that in situations where an individual is not available for a direct comparison with a biological sample, any maternally related individual may provide a reference sample. http://www.mitotyping.com/dna.htm Jun 06 03, 10:38 PM