The Mitochondrial Eve

Who will she be?

Screen reader users should click the D-link at the end of the description of this exercise. Then come back and read the Thought Questions towards the bottom of the page.
The mitochondrial genotype is inherited through the cytoplasm, and so follows the female line through the generations. Due to random sampling, mitochondrial genotypes get "lost", and so the number gradually decreases (irregularly) through the generations, and finally one mitochondrial genotype is "fixed". (New ones are generated by mutation, which is not considered in this exercise.) This produces a Mitochondrial Eve (last accessed 31 Dec. 2015) - a "retroactive" name for the most recent female ancestor of all of the species' cytoplasm. An essay by Krishna Kunchithapadam (last accessed 31 Dec. 2015) provides additional discussion and references on this topic. (Note that this exercise investigates the "prospective" inheritance of the mitochondrial genotype.)

Starting with 10 female parental mitochondrial genotypes (represented by different background colors - the males are gray since their mitochondrial genotypes are not passed on to the next generation) the offpring are produced by randomly sampling uniformly (with replacement) from the parental generation. The mitochondrial genotypes for all the offspring are visible, but only the females are counted. After the Offspring generation is produced, it can be "promoted" to be the new Parental generation, and the process repeated to form succeeding generations. The number of mitochondrial genotypes in each generation is recorded in the box at the bottom of the page.

It may take many generations, but eventually there will be only one mitochondrial genotype in the offspring generation. Did you guess right? [D]

  Parents   maternal mitochondrial genotypes

  Offspring   female mitochondrial genotypes

Thought Questions

Please send comments to   --henry schaffer
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Copyright © 1999, 2000, 2006, 2011, 2015 by Henry E. Schaffer
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