Month: June 2014
An explanation of DNA testing for genealogy
DNA testing for genealogy has been very popular, lately, as a tool to delve further into ones family tree. In 2011, I had my mitochondrial DNA or mtDNA tested, as well as, autosomal testing through FamilytreeDNA.com.
Mitochondrial testing is useful in tracing one’s maternal line to its origin. Mitochondrial information is found in our cells and passed from mother to child. This information doesn’t change making it possible to trace our maternal lines.
In this chart, the maternal information is passed from a mother to a son and daughter. The daughter can pass the mitochondrial information to her son and daughter but the son does not. In other words, for me to get mtDNA information for my mother’s maternal line, my brothers and I could have taken the mtDNA test. My daughter and my son can take the test to get the same information but by brother’s children can’t because they could pass the mtDNA information on to their children.
Ydna testing is done to trace male inheritance. Only males can take this test as Y chromosomes are only passed from father to son. I can’t get ydna information of my father’s lineage but my brother can.
When these tests are done, you are given a haplogroup designation. This map gives us an idea of the migration and evolution of different mitochondrial lineages beginning with “mitochondrial Eve” from whom all modern humans are believed to be descended from on the maternal lines. Eve is believed to have been born 200,000 years ago in East Africa. While she wasn’t the only female living at the time, all other female lines failed to produce continuous descendants with their mitochondrial DNA.
Over time, Eve’s offspring began to migrate outside of this part of Africa. With time particular mutations happened within the mtDNA resulting in subgroups. With these subgroups, it’s possible to trace your maternal lines to different parts of the world.
My mtDNA haplogroup is L3b1a. The first genetic mutation of Eve is L0, then L1, L2, and L3. Because I did the full sequence of my DNA I have extra information on my maternal lineage which primarily West African with my coding region (another part of the DNA tested) matches me with indigenous Berbers of Morocco and Egypt.
FTDNA provides you with information about matches on the mtDNA test. In my case, where L3b1a goes back at least 20,000, my matches may be too distantly related to find our exact connection but it gives me more clues on my lineage. Most of my matches are Bantus in places like Sierra Leone, Camaroon, Chad and I even have matches in Syria.
FTDNA offers autosomal testing through their FamilyFinder test that theoretically gives you your ethnic breakdown according to your chromosomes. This information comes from both your mother and father and should reflect the past 125 years or 5-6 generations back. For some population groups, there are filters that help distinguish matches that appear close genetically but in actuality are more distant on paper. Where there are generations cousins marrying cousins as in the case of royal families, etc, there is the possibility that the results reflect information much further than 125 years. In my tree, I have many 3rd and 4th cousins marrying so I’m pretty sure that my Afghani line wasn’t very recent.
Of my matches on FamilyFinder, some are of Cape Verdean origin, while some people are of Eastern European and Jewish origins. How I match Hungarian, Polish and Ukranians has been a bit tricky but what’s interesting is that we all descend from the same person since we all match on the very same spot on the same chromosome (19). I have African American matches, one of who has only been able to trace one line to an enslaved person around 1860 in South Carolina. The thought that his ancestor was possibly family to someone in my tree is intriguing in that it may be a way to connect to my enslaved ancestors.
Exploring my DNA has been very interesting, to say the least. It’s helped to answer many questions, expand my family tree and to create even more questions. My hope is that questions about “what is a Cape Verdean” can be answered in terms of its history and what groups of people were instrumental in its creation. But most of all, rather than defining Cape Verde in terms of its uniqueness and setting it apart from the rest of the world, it should strengthen our humanity. At the end of the day, we are all connected.