Mutation rates
“Mitochondrial DNA appears to mutate much faster than expected, prompting new DNA forensics procedures and raising troubling questions about the dating of evolutionary events.” “...Regardless of the cause, evolutionists are most concerned about the effect of a faster mutation rate.  For example, researchers have calculated that "mitochondrial Eve"‑‑the woman whose mtDNA was ancestral to that in all living people‑‑lived 100,000 to 200,000 years ago in Africa. Using the new clock,
Gibbons, Ann, “Calibrating the Mitochondrial Clock”, Science, Vol 279, No. 5347, Jan 1998, pp. 28 ‑ 29.
                        she would be a mere 6000 years old…” 
Mitochondria: organelles in the cell that convert energy to produce ATP (site for cell respiration)