12923andme's Countries of Ancestry feature
- Jun 30, 2013While those of full Mexican ancestry are mostly Iberian and Native American sometimes you can match specific segments of your dna that are associated with specific countries. These segments of dna are likely old segments associated with drift and possibly selection.
Sorting by starting segment helps with oberving common segments while making sure the matches or near matches are on the same chromosome:
This sequence show the country of origin of the four grandparents and wheather they are of Ashkenazi, then the chromosome, then the start point and end point, then the segment length in mega base pairs and then the segment length in cM or Centimorgans.
Cuba Cuba Not Provided Not Provided FALSE FALSE FALSE FALSE 11 2.6 5.2 2.6 5.4
Not Provided Not Provided Not Provided Not Provided FALSE FALSE FALSE FALSE 11 2.6 5.2 2.6 5.4
Italy Italy Not Provided Not Provided FALSE FALSE FALSE FALSE 11 2.6 5.2 2.6 5.4
Cuba Cuba Cuba Cuba FALSE FALSE FALSE FALSE 11 2.6 5.2 2.6 5.4
The above 4 matches are exact matches to mine and since one has 4 grandparents in Cuba and another has 2 Cuban grandparents it appears to be a Cuban in origin given the migration pattern of our Mexican ancestors. Cubans being an island population have very specific dna because of drift.
The above matches could be related through an ancestor that went to Cuba early enough to leave dna to pick up a match now but this seems unlikely. The other thing is this is a very small segment as a segment of 10cM is considered recent ancestry and this is 5.4 cM but I don't believe the exact length is a coincidence but a segment from a specific population. The not provided introduce an element of uncertainty and must be treated as such when it comes to drawing conclusions from them solely.
Here is another one:
Palestinian Territory Palestinian Territory Lebanon Palestinian Territory FALSE FALSE FALSE FALSE 7 12.5 15.7 3.2 6.2
Portugal Portugal Portugal Portugal FALSE FALSE FALSE FALSE 7 12.6 15.6 3 5.5
I will not include the Ashkenazi matches as so far with the many of full Mexican origin that I am sharing with we all seem to have these matches. It is important to note that they match us in the sense that our common matching segments are more likely to be of Sephardic origin. Until we can compare our dna to the Sephardic then we are left with the question of how much of our dna is from them.