Ancestry Assignment of Chromosomal Segments: The Example from my Genome

Here is another result from personal genotyping at 23andme.  As a part of the service they infer the population of ancestry of chromosomal segments based on allele frequency probabilities in comparison to reference population samples (I'll make a separate post about the details of that later).  Here is my result after the chromosomes are phased with my parents genotypes:

FAR-ancestry

I will digress a bit into some personal family history to provide some background: We have always known about the Native American (Cherokee) ancestry from my paternal grandmother's father's side of the family.  My grandmother and her ancestors were from the rural Southern Appalachians and she even knew the Cherokee words for some wild plants, etc.  Years ago when they were still living I asked both of my grandmothers more about our family history and that is when I first heard the term "Black Dutch" also mentioned, which, one step leading to another, led me to look up information about the Melungeons (Black Dutch also has a different meaning on another side of my family that I will bring up in a later post).  Melungeon history is enigmatic but various family and historical traditions contain references to Portuguese, Mediterranean, Spanish and Cherokee ancestors.  It is also well known that the Spanish had a colonial presence in the South long before the English colonists spread into the area, including the Appalachian foothills with the Spanish Fort San Juan, which is currently being studied by my alma mater Warren Wilson College and former professor David Moore.  The interesting thing about my genetic result is that the Native American sections are flanked by Southern European segments and specifically "Iberian" on chromosome two, suggesting an association between my Spanish/Portuguese and Cherokee ancestors.  There is also an apparent North African segment on Chromosome five (also from my father's side of the family) which also fits into Melungeon origins.  For example an Appalachian Melungeon family, the Baldwins, have preserved a Levantine sash that has been passed down in their family for centuries, suggesting a Middle Eastern connection.

sash1

Confirming family history is fun, but the surprises are also entertaining.  The real surprises for me are the Finnish ancestry and the tiny segment of South Asian ancestry; we have (almost) no family/genealogy history of either, but I will go into more detail about those later.

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