[Dean's World] Shay: The Greatest Journey

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Posted by Shay:
The Greatest Journey
http://www.deanesmay.com/posts/1141753070.shtml


   [1]This month's edition of National Geographic magazine discusses how
   genetic markers passed down to us from our ancestors are leading
   scientists back across time to trace human migration patterns: "By
   comparing markers in many different populations, scientists can trace
   their ancestral connections. In most of the genome, these minute
   changes are obscured by the genetic reshuffling that takes place each
   time a mother and father's DNA combine to make a child. Luckily a
   couple of regions preserve the telltale variations. One, called
   mitochondrial DNA (mtDNA), is passed down intact from mother to child.
   Similarly, most of the Y chromosome, which determines maleness,
   travels intact from father to son. The accumulated mutations in your
   mtDNA and (for males) your Y chromosome are only two threads in a vast
   tapestry of people who have contributed to your genome. But by
   comparing the mtDNA and Y chromosomes of people from various
   populations, geneticists can get a rough idea of where and when those
   groups parted ways in the great migrations around the planet."

   Interesting. Just yesterday I took a mitochondrial DNA test to trace
   the specific African ancestry of my mother's mother's mother's
   mother's line, back through the generations. [2]The same lab that did
   the mitochondrial and Y-chromosome DNA tests for the nine famous black
   Americans in last month's "African American Lives" series on PBS is
   doing my test. Unlike other branches of my family tree - three of
   which we can trace back to 1820 to 1830 in the antebellum South - my
   matrilineal line can be traced back to C.D., my maternal
   great-great-great grandmother born in rural Mississippi in 1845.

   In four to six weeks - maybe earlier - my test results will return. I
   am excited and nervous. Since I was a child, I have wanted to travel
   to Africa. In the past couple of years, I have stated that I will
   first travel to the specific country or countries which correspond to
   the modern-day locations of my ancestral links. What ancestry will my
   mitochondrial test show? Will there be an exact match for only one
   tribe as was the case for Quincy Jones? For several tribes, as was the
   case for Oprah. Will I unfortunately be among the 15-20% of test
   takers whose DNA test comes back inconclusive, which happened to
   astronaut Mae Jemison?

References

   1. http://www7.nationalgeographic.com/ngm/0603/feature2/index.html
   2. http://www.deanesmay.com/posts/1139512580.shtml