At locus #930 I have the chimp marker instead of the human one!

     Yes, as strange at it sounds, I encountered something a bit crazy in my own mitochondrial DNA at location #930.  I've been comparing my genome with other humans to determine variation, but also with chimps and bonobos found in the databases at NCBI, and the Neanderthal and Denisovan samples extracted under the direction of Svante Paabo at the Max Planck Institute for Evolutionary Biology in Leipzig, Germany.  Step by step, base by base, I'm comparing the data, and found 30 distinctive markers separating chimps and humans among the first 1,008 base pairs analyzed.


Jane Goodall spent her life exploring the psychology and sociology of chimpanzees

    But at marker #930 something strange occurs.  Humans have a G (guanine) in this position.  Chimps and bonobos have an A (adenine).  However, my own DNA has an A!  I have the chimp marker, while humans (or to be clear, most humans) have a distinctive human marker.  How could this be? 
    It so happens that my mitochondrial DNA signature belongs within a specific haplotype known as T2b.  The mutations in my DNA can be arranged chronology and traced back to a founding population in Africa, ultimately connecting to every human on Earth--if you trace back far enough. The same is true for your own haplotype. My haplotype T2b descends from T2, which descends from T, which descends from JT, which descends from R, which descends from N, which descends from L3 all the way back to Africa. 
    So how did I end up with a supposedly distinctive chimp marker?  Well, apparently my value 930A was not original to my ancestry.  Haplotype T2b is defined by a mutation G930A (meaning the "G" mutated to an "A" in position 930).  It so happens that the "A" is the chimp value, seemingly by coincidence.  This doesn't mean I have more chimp ancestry than you.  It only means that I have a specific marker that mutated back to the value found in chimps today.  Back before chimps and humans existed we shared common ancestor.  I'm uncertain if that ancestor had a "G" or an "A" at position 930.  Therefore, I place G/A in red in that position on my report found here.  As I expand my study to include other diverse primates, I may be able to determine an original value.  After all, there are only two choices.  I have never found a "C" or "T" in this position. Perhaps the mutation occurred in the chimps from an original "G."  Perhaps the mutation occurred in humans from an original "A."  Perhaps this marker switches back and forth in both populations in prehistory.
    I don't have many chimp samples to work with, but so far all chimps I've studied have an "A" at position 930.  On the human side I have 20,600 samples, and I found this "back mutation" to the chimp value in seven lineages, in haplotypes L1c6, L5a1, L2a1c1, M1a1b, M44a, D4h3a1a, and T2b. It includes less than 3% of the world's human population.  Haplotype T2b is the most populous of these seven lineages that share G930A.  It is concentrated in central Europe.
    I think I can confidently state that marker 930 has shifted from the "G" to the "A" throughout human history--at least in seven instances.  Compared to most mitochondrial DNA markers, this position mutates rapidly.  Part of the outcome of my study is to determine which markers mutate rapidly and which markers are especially stable.  In comparative genetics, a difference in a fast mutating marker is not as significant as a difference in a slow mutating marker.  I have access to 20,600 human genomes, upon which to determine which markers mutate more often than others.  That's quite a lot of data.  More data allows for better conclusions.  What was thought of as a distinctive chimp marker is actually part of the DNA that overlaps between humans and chimps.  There are other markers like this as well.  I notate them all, base by base,  in my report.