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Haplogroups Yield Ethnic Admixture
A Workpaper In Progress by Herbert Holeman, PhD.
Notes Posted .
How a haplogroup defines your branch on the human family tree was discussed in the previous workpaper. In this workpaper I focus on the ethnic flow of branches of genetic markers on the human family tree by haplogroup. In particular I do so for the paths of my clans in from China, to present-day Southeast Asia, and MesoAmerica with Iberian admixture.
Discussion
As discussed earlier, when people from one geographic location have children with people from another location, the DNA of their children becomes a mixture of the DNA from each group.
Over the passage of time a distinct haplogroup is formed by this admixing process repeated by many subsequent generations. Thus, the genomes of present-day descendants contain segments of DNA inherited in a haplostream from each admixing group.
Figure 15
DNA Haplogroup Markers
It is from these bits of DNA left from mixing of populations downstream, that is to say, closer in time to the present, that DNA tests produce estimates of the ethnic admixture of who our ancestors were and where they lived.
To quote noted geneticist Dr. Adam Rutherford, "These tests can reveal where DNA like ours can be found on Earth today." As for the accuracy of DNA tests, I concur with genealogist Amy Johnson Crow, "the estimate is good on the continental level. Getting down to the country or region is much more problematic."
Table 1 reveals my primary admixture at the continental level as consisting of three major ethnicities. More specifically, the tables and figures define it to be Southeast Asian and Hispanic (Iberian, and MesoAmerican).
Another view of ethnic admixture is provided by chromosome painting, which matches up biogeographical populations with the human genome. Following are the admixture estimates made by the DNA Company, 23andMe, with 90% confidence. They depict my 23 pairs of chromosomes ordered by length, size, and colored to estimate the geographical location of my ethnicity.
Ethnic Admixture
by Chromosome
Accordingly, Figure 17 represents my East Asian & Indigenous American ethnicity. Chinese & Southeast Asian (48.2%) accounts for the greater bulk of my ethnic admixture.
Philippines - Austronesia
Ethnicity by Chromosome
Figure 18 represents my European ethnicity (33.1%)
Iberian Ethnicity
by Chromosome
Figure 19 represents my Indigenous American Ethnicity (10.6%).
Americas Indigenous Ethnicity
by Chromosome
Regarding these ethnicity estimates, I concur with the view of anthropological geneticist, Dr. Deborah Bolnick: "If a test-taker is just interested in finding out where there are some people in the world that share the same DNA as them, then these tests can certainly tell them that."
To that point, however, issues arise in DNA company ethnic geographic selection, ethnic population labeling, and reference population timeframes.
Geographic Selection Issues
The geopolitical boundaries differ by company in calculating admixture percentages assigned to test-takers. Arguably, this accounts for much of the variance among company estimates. In my case, tables 2 and 3 are such examples.In Table 2 calculations for Iberia, the 23andMe Company combines the population count of Spain and Portugal, while the Ancestry.com Company calculates the population individually for Spain, Basque, and Portugal.
Iberia is also an example of the complexity in defining ethnicity. Bronz says "people who live in Portugal, Spain, France, Morocco, Italy, and Algeria can, and usually do, show strong genetic links to the Iberian Peninsula. Moreover, People who are native to the Iberian Peninsula DNA region are generally very admixed as well, showing only about 51% Iberian DNA, on average. A person from this region is likely to have DNA from South Europe, Great Britain, Ireland, North Africa and West Europe, along with others."
Ethnicity Assignment Issues
Ethnic description of surveyed populations differs among companies. It complicates describing a test-taker's ethnicity. Genetic genealogist, Kitty Cooper points out, "sometimes East Asian ethnicity is, in reality, American Indian, and South Asian might be Gypsy or Indian from India. Scandinavian might be British or North German, and British and Irish might be Scandinavian."In Table 3, the geopolitical Native American populations are not clearly delineated, patricularly by the company, 23andMe. In my case, the descriptive distribution among the companies is best defined by Ancestry.com.
Population Timeframe Selection Issues
Companies come at selecting ancestral timeframes from different perspectives. For the most part, the companies 23andme and Ancestry.com are oriented on recent genealogy, around 500 years ago.
Summary
This view of recent biogeographical world populations distribution limits my research, which is exploring the origin and cultures of my genetic ancestors. Fortunately, the XCode Company and FamilyTreeDNA Company strive to give ancestral information deeper than 500 years.
Your comments and suggestions on this workpage appreciated. Please email me directly at: holeman1@gmail.com