HAPLOGROUPS AND MARKERS IN TESTING FOR ANCESTRY


The autosomal DNA test enables analysis of biogeographical ancestry as it is a search for ancestry inherited from all my maternal and paternal ancestors. Accordingly, it infers my genetic ancestry based on geographical origins.

As for genealogical ethnicity, Roberta Estes: adds, "I've said this before, and I want to say it again. Ethnicity is the least precise and the least accurate of DNA tools for genetic genealogy. Noted Anthropology professor, Deborah Bolnick, agrees. She says, "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."

Autosomal DNA accomplishes this through the use of genetic markers organized by haplogroups which divide the world by geographic locations. one's genetic genealogy is portrayed by a set of genetic markers depicted in the form of a haplogroup tree with its markers as branches.

Figure 3
My Genetic Ancestral Tree
By Parental Haplogroups and Genetic Markers

Ancestry

Haplogroup Ancestral Tree

The tree in Figure 3 depicts my ancestral heritage categorized by haplogroups from which roots my ancestry stems. Each such haplogroup is a representation of a genetic population group of people who share a common ancestor and its conceptual structure is based on the assertion, "All people alive today belong to distinct haplogroups of people belonging to the same haplogroup and can trace their descent to a common ancestor and even a specific place where that ancestor may have lived.". Haplogroup designations are assigned geographically which in my case, is haplogroup B for my maternal line of descent and haplogroup O for my paternal line of descent.

Marker (AKA: SNP -- Single Nucleotide Polymorphism)

A SNP is a specific location on a chromosome and are depicted on the branches of a haplogroup ancestral tree. A SNP comes about when a descendant has a genetic trait that his ancestor does not have. This new trait is referred to as a mutation and as the result of this genetic variation, the decendant has derived a new SNP. Thus, the decendant has formed a new branch in his haplogroup to be linked to a geographic location. "If you and someone else have the same SNP, you share an ancestor who was the first to have that mutation, and eventually passed it on to you." For reading ease, it is common practice to refer to a SNP by the name of its Genetic Marker because a SNP designation can be a complex series of letters and numbers.

My Haplogroups and Markers

In my case, DNA autosomal tests place my genetic ancestry maternally in Haplogroup B and paternally in Haplogroup O, both of which originated in what is present day China.

My maternal ancestry stems from the woman who gave rise to haplogroup B in mainland China ~50,000 years ago. Her descendants carried the haplogroup B4 marker B4b1 eastward into Southeast Asia. The B4b1 marker has been found mainly in populations of southern China and Southeast Asia, especially the Philippines and the Austronesian speakers of eastern Indonesia and the aborigines of Taiwan and Hainan, China. Moreover, the B4b1 marker also gave rise to the B2 marker, my present maternal marker, ~15,000 years ago which spread into the Americas.

My paternal genetic ancestry stems from the man in eastern Asia ~45,000 years ago bearing the haplogroup marker O-M1359. He gave rise to haplogroup O in present day China. For thousands of generations, his descendants stayed in east Asia where they have become the majority of the Han Chinese, Japanese, and Taiwanese. That said, he and his offspring family of markers over the ages have lived in different places in the centuries following his genetic origin but have remained in Asia.

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