Rochester, NY
23 April 2014
 
    King Richard III

    His power challenged and overthrown, pierced by “humiliation wounds,” his legacy to be tarnished by his successors, Richard III’s lifeless body was draped over the back of a horse, to be carried to parts unknown. For hundreds of years, nobody has ever known just where the last Plantagenet King finally laid down to rest.

    Uncovering that mystery took detective work. It took a lot of convincing of skeptical colleagues. It took forensic analysis and most definitively of all, it took mitochondrial DNA evidence:

     DNA from the skeleton matched a sample taken from a distant living relative of Richard’s sister. Geneticist Turi King said Michael Ibsen, a Canadian carpenter living in London, shares with the skeleton a rare strain of mitochondrial DNA. She said combined with the archaeological evidence, that left little doubt the skeleton belonged to Richard.

    What is mitochondrial DNA and why is it so authoritative? The answer is an amazing bit of cellular evolution that takes place millions of years before the first humans even thought to stab each other with sharp metal things.

    Mitochondria are the fuel cells of the cellular world. Every cell in your body has several mitochondrion, whose role it is to convert energy from glucose into a form that the cell can use, called ATP or Adenosine Tri-Phosphate.

    But what is really interesting about mitochondria is that they behave like a separate living organism within the cell. They have their own discrete nucleus with its own DNA, their own cellular wall that performs the same functions as the wall around the main cell, ..and they even reproduce in the classic cell splitting bacterial way:

    Bacterial and mitochondrial reproduction. Image courtesy Berkley University

    This has led scientists to believe that mitochondria are in fact their own separate species of symbiotic life. Somewhere along the line, scientists believe that a proto-mitochondria was enveloped by another type of cell and rather than being killed, ended up helping the host cell out. Scientists have observed bacteria being absorbed by amoeba in this same fashion. The result was a form of inter-species cooperation that is beyond ubiquitous. All forms of eukaryotic life – cells which have nuclei, which is to say every cell in your body, your dog’s body and every plant or tree – have mitochondria. That leaves only bacteria and archaea without mitochondria.

    So, why does this all matter in the discovery of a long-dead king? Because mitochondria reproduce asexually, are contained in the ovum (an egg cell) and are therefore passed from mother to child exclusively. Whereas the rest of your DNA is half your mother, half your father, your mitochondrial DNA is all momma. And because it is copied asexually, it is very, very consistent over hundreds and even thousands of generations. The DNA that make your mitochondria work are probably not all that different from relatives so far back, your Ancestry.com profile doesn’t even include them.

    Thus after hundreds of years, a controversial noble’s irrefutably ignoble resting place beneath a modern-day parking lot was discovered.

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