Mitochondrial DNA and Human Evolution

In 1987, geneticists Allan Wilson, Rebecca Louise Cann, and Mark Stoneking published the article "Mitochondrial DNA and Human Evolution", in which they showed that all modern, living humans can be traced back to a single woman living in Africa, approximately 100-200 000 years ago, later coined 'Mitochondrial Eve'. They found this evidence by sourcing mitochondrial DNA from 147 humans, living in vastly different areas of the world- Asia, Europe, New Guinea, Australia, Africa, from placentas. Mitochondrial DNA differs from 'regular' DNA in that it is only passed down maternally, from mother to daughter, and does not recombine during meiosis. This means it doesn't change between offspring aside from mutations- however, the geneticists found that the mutations occurred fairly consistently and were able to actually use them to their advantage, like a 'biological clock' where they could get an accurate idea of the timeline and trace the lineage of the shared mtDNA way back until they found this last common ancestor, the "Mitochondrial Eve". The "Mitochondrial DNA and Human Evolution" article suggests this single woman's bloodline or 'lineage' by chance, survived over all other lineages, was continually passed down from mother to offspring, not changing aside from mutations, and expanded all over the world to eventually be present in every single currently living human's mtDNA. 

Source:

Haskett, D. (October 10 2014). "Mitochondrial DNA and Human Evolution" (1987), by Rebecca Louise Cann, Mark Stoneking, and Allan Charles Wilson. 

Retrieved from: https://embryo.asu.edu/pages/mitochondrial-dna-and-human-evolution-1987-rebecca-louise-cann-mark-stoneking-and-allan