July 14, 2008
Relative Connection: DNA Tests Trace Family’s Lineage, With Few Surprises
By Michael Janairo, Albany Times Union, N.Y.
Jul. 14--In my family, the stories of our ancestries are tied to faraway people and places.
New DNA tests, however, offer other ways of exploring our ancestries. So we signed up with the National Geographic's Genographic Project to see what the DNA tests would reveal.
The project aims to trace the migratory routes of all humans by collecting the DNA of indigenous people, and it offers a public participation kit (for $99.50) that traces the routes of an individuals' deep ancestors, relatives from long before history began.
The kits can analyze either mitochondrial DNA (mtDNA), which is passed down from moms to sons and daughters, or Y-chromosome DNA (Y-DNA), which is passed down from dads to sons, but not daughters because females don't have Y chromosomes. We bought four kits to test: my wife's mtDNA; my stepson's Y-DNA; and my mtDNA and Y-DNA.
The test kits come with instructions, swabs and consent forms. We swabbed the insides of our cheeks, dropped the samples into a vial of solution, filled out the consent forms, mailed them off and waited.
A couple of months later, we entered our test kits' codes onto the Genographic Web site and got a letter code identifying our haplogroups, or specific genetic mutations that define a branch in the human family tree; maps showing our ancient ancestors' journeys; and an overview of who those ancestors may have been.
In our Y-DNA results, my stepson (haplogroup I) and I (haplogroup O3) share an origin with all other human males with the "Eurasian Adam" from between 31,000 and 79,000 years ago in eastern Africa.
His most recent deep ancestor is from 20,000 years ago in southeastern Europe, part of the migratory path from the Middle East, through the Balkans and into Central Europe. His ancestors may be linked to the prehistoric Gravettian culture, named after a site at La Gravette, France, where a set of tools was found. And, the report says, it's also possible the Vikings descended from his most recent ancestor.
My most recent deep ancestor is from 10,000 years ago in China, around the time rice farming began. I share this ancestor with more than half of all Chinese men, and the spread of his descendants coincides with the spread of rice agriculture to Japan and Southeast Asia, which includes my father's homeland, the Philippines.
As for the mtDNA tests, my mother's DNA (haplogroup U5) and my wife's DNA (haplogroup K) both begin with the "Mitochondrial Eve" about 150,000 years ago in eastern Africa.
About 50,000 years ago, my wife's and my mother's ancestors diverged. My mother's ancestors headed into Scandinavia, especially Finland. Nearly 50 percent of the Saami people, indigenous reindeer herders of Northern Europe, share my mother's mutation, as do some members of the North African Berber populations in Morocco. Ireland doesn't get a specific mention, though the report does say the mutation is found, though rarely, outside Scandinavia.
My wife's ancestors, on the other hand, crossed the Caucasus Mountains in southern Russia and moved to the steppes of the Black Sea. Her most recent ancestral genetic mutation is linked to three of the four major Ashkenazi Jewish founding lineages. So the test confirmed what we already knew -- my wife's Jewish.
None of this impressed my wife. She remarked that all we did was spend this time and money to find out we're all from Africa.
I sent my results to my siblings, who share my deep ancestry. My sister wrote, "Although I find it interesting, I am not surprised by the report and, call me a spoilsport, but I do not find it really makes any sort of impact on who we are or who I am."
One of my brothers wrote, "Cool, we are Finnish rice farmers! No wonder I like to put cheese on my rice!"
Jonathan Marks, an anthropology professor at the University of North Carolina at Charlotte, co-authored a cautionary article about genetic ancestry tests for consumers, which was published in the journal Science, and via e-mail elaborated on the limitations of the deep ancestry genetic test.
He wrote, "The problem is this: You are equally related genetically to all four of your grandparents, but with mtDNA, you are a clone of one of them, and unrelated to the other three. That is because you inherit mtDNA from your mother, but not from your father. As you go back to prior generations, your ancestors increase exponentially (every ancestor had two parents), but your mtDNA is only identifying one ancestor in every generation. Twelve generations ago, say around 1700, you had literally thousands of ancestors, but mtDNA only detects one of them."
Perhaps the novelist A.M. Holmes put it best when she wrote about participating in the Genographic project in her memoir "The Mistress's Daughter": "I feel like I spent $100 to find out what I already know -- I am related to everyone."
Michael Janairo can be reached at 454-5629 or via e-mail at [email protected]
Tracing the markers in a tree of genetics
Haplogroups, according to the National Geographic Genographic Project's Web site, are branches on the tree of human migration. They are defined by mutations that "link the members of a haplogroup back to the marker's first appearance in the group's most recent common ancestor."
So when someone mails in a test kit to the Genographic Project's partner Family Tree DNA, which has a test lab at the University of Arizona, the DNA is analyzed to discover that person's haplogroup.
The following information explains the science behind that analysis and comes from both the Genographic and Family Tree DNA Web sites.
--A human body has 50 to 100 trillion cells. In each cell are organelles including a nucleus, which contains the genetic material in chromosomes, and mitochondria, which are a source of energy for cells and are called "cellular power plants."
--Chromosomes carry genetic information in strands of DNA called genes. Humans have 22 pairs of chromosomes, identified by numbers, and one pair is the sex chromosomes, XX for women, XY for men.
--The strands of DNA are in the form of a double-helix staircase, with each stair composed of the chemical bases of adenine, cytosine, thymine and guanine. Some sequences of these bases, identified with the letters A, C, T and G, form genes, which determine cell functions.
--Genetic information gets passed down from a mother and father to a child, through a genetic recombination process. Some parts of the genome, however, aren't recombined, so they are passed down unchanged. For a father, an unchanged sample of his genetic information is passed to a son through the Y-chromosome. For a mother, the unchanged genetic information is passed to both sons and daughters through the mitochondrial DNA.
--However, sometimes a mutation can occur in the Y-DNA or the mtDNA. If a mutation is passed down to later generations, it acts as a genetic marker, or a haplotype.
--Genetic markers can be identified in DNA sequences and then traced back in time to their origin -- the most recent common ancestor of everyone who carries the marker.
--For Y-DNA tests, 12 markers are examined for specific genetic sequences, called DNA Y-chromosome Segments (or DYS), and for the number of times that sequence repeats, or alleles. These sequences determine a test-taker's haplogroup on the paternal side.
--For mtDNA tests, the results are compared against the Cambridge Reference Sequence, or CRS, which was first created in 1981. Any variation from the CRS is marked as a mutation, and is used to determine the test-taker's haplogroup on the maternal side.
- Michael Janairo
Web of information
More information about genetics and genealogy can be found at the Web site for the International Society for Genetic Genealogy at http://isogg.org/
The National Geographic Genographic Project Web site:
The Genographic Project isn't the only deep ancestry DNA product on the market. Other products include:
*Family Tree DNA: The partner with the Genographic Project offers analyses that examine more genetic markers and can examine ethnic histories. Prices range from $129 to $839; http://www.familytreedna.com/
*Ancestry.com DNA Test: Analysis of mtDNA and Y-DNA varies in price from $149 to $199; http://dna.ancestry.com/
*DNA Heritage: Analysis of mtDNA and Y-DNA varies in price from $129 to $219; http://www.dnaheritage.com/
More test products can be found at the international society's Web site, for mtDNA at http://www.isogg.org/mtdnachart.htm and Y-DNA at http://www.isogg.org/ydnachart.htm
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