We are familiar with the use of DNA testing for forensic evidence and paternity disputes. We no doubt have also heard of situations where such tests have been used in controversial ways. But for genealogical research these tests can be helpful in tracing family, especially where the oral or documentary evidence is missing. In this second blog I would like to outline what DNA tests are and how they have helped me in my family history research.
When the historical records are not readily available
One of the most frustrating things I found with trying to trace my St Lucian heritage, was how difficult it was to find genealogical records. The country is now involved in a project to digitise this information and make it available on-line but at the time of writing it is still in progress. It is even more frustrating when you learn that friends and colleagues (in Europe, North America and some parts of the Caribbean) are able to, literally from the comfort of their homes, trace family trees going back decades and in some cases centuries.
I heard of DNA tests referred to in Genealogy programs like "Who Do You Think You Are?" or "Finding Your Roots". But I never gave doing one much thought until the day I had a conversation with a work colleague. We were talking about family history and he mentioned that he had taken a test which not only showed his ancestral roots, but listed a number of DNA relatives; these DNA relatives were potentially 1st to 4th and more distant cousins of his. This pipped my interest as it seemed to offer at least a partial solution to my research problems.
DNA and your Family Tree
We all belong to a biological family tree and it is possible to determine ancestry by analysing the DNA passed down generations. DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. In the nucleus of each cell, the DNA is packaged into thread-like structures called Chromosomes.
There are different ways in which DNA can be of use in determining your ancestry. A person has 23 pairs of chromosomes containing DNA plus we have some more DNA that can be tested in something called the mitochondria (mtDNA). Mitochondria are organisms which produce a cell's energy. Chromosomes 1 through 22 recombine for reproduction. The 23rd chromosome pair are related to a person's sex and are designated as XX for a girl or an XY for a boy.
The following diagram shows the 23 pairs of chromosomes that each of us have:
Autosomal DNA passes down from all ancestors. Each person receives 50% of their DNA from each parent, but the allocation is random. So siblings born of the same parents will have different combinations of their parents DNA from each other.
Mitochrondrial DNA is inherited by all children only from their mother and provides a way to trace maternal ancestry.
Y-DNA represents the Y chromosome which men inherit only from their father. This can be used to trace paternal ancestry.
Finally X-DNA represents the X chromosome which both men and women inherit from their mother, and women only inherit from their father.
So there are DNA tests that can assess your Autosomal DNA, Y-DNA, X-DNA or Mitochrondrial DNA.
Where can you get DNA tests for Genealogy done?
A search on the Internet will provide you with a list of companies offering DNA tests. But which should you choose for genealogical research?
My first test was undertaken with 23andMe. You need to set up an account at the 23andMe website and order a testing kit. Once the kit arrives you just need to provide a sample of saliva and return the sample in a protective container. A few weeks later you will be notified that your results are available. They can only be viewed online, no certificate or other paperwork is sent out.
The second test was with AncestryDNA. As with 23andMe, you provide a sample of saliva and your results, when ready can be viewed online.
Both were Autosomal (Admixture) tests. Each providing a ethnicity breakdown showing which parts of the world my ancestors came from for both sides of my parentage. The tests also provided a list of DNA relatives - other people sharing similar elements of DNA. In addition 23andMe provided health traits and risks.
See the sections at the end of this article for a list of companies providing DNA tests for genealogy.
What my tests showed me
The Caribbean has a very diverse population. In this region you find ethnicities which include the indigenous Native American people, as well as those for people who have arrived from Africa, Asia and Europe in more recent centuries. I had no doubt of my African heritage but where on the African Continent did my ancestors come from and what else was I?
Both tests gave a fairly consistent ethnicity breakdown with 78% of my ancestry from Africa, approximately 20% from Europe and the remaining 2% representing Native American/Asian with some undetermined elements. I particularly liked that these tests also give me regional breakdowns.
23andMe only detailed the European element of my ethnicity.
AncestryDNA provided much more detail about all the elements of my ancestry.
The most surprising thing which came out of the results was how varied my regional makeup was. For instance the test suggests that I have African ancestors from the countries we now know as Senegal, Mali, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon and Congo. Benin/Togo, Mali and Cameroon/Congo being the main components. Wow - the "united nations" is literally written into my genes! The European variation whilst a much smaller part of my genetic makeup was no less surprising pointing to ancestry from Scandinavia and Western Europe!
Your DNA relatives
When two people share identical segments of DNA, then they share a recent common ancestor. The length and number of these identical segments can be used to determine the relationship between relatives. So it is then possible to find DNA "cousins" by comparing your DNA with others who have taken the same test. Both 23andMe and AncestryDNA tests provide such a list.
The 23andMe test put me in touch with a first cousin who I didn't know about.
Both my parents have taken a AncestryDNA test and my hope is that this will help to uncover other relatives.
But care must be taken
After a few generations (as little as three), the use of DNA to match relationships become more difficult. So test's which claim to match you with a historical figure should be treated with scepticism. Also DNA tests are estimates and the technology used is constantly evolving. So DNA test should be used to supplement other genealogical information you may have about your family or the region in the world they may have come from. It shouldn't be considered an end in itself!
So how has these tests helped me?
Seeing where in the world my ancestors came from has been very fulfilling.
Identifying a first cousin (the grandson of a paternal Aunt) has been one of the most important things to come out of my DNA tests. So as far as I am concerned, the tests can link you with relatives! I still have more work to do in communicating with the third to fourth DNA cousins identified by 23andMe and AncestryDNA, as we are very likely descendants of common second or third grandparents. My hope is that this could help me to extend by Family Tree learn more about my family history.
Organisations providing DNA tests for genealogical research
There is a wealth of information readily available about DNA testing for the purpose of uncovering your ancestors. Just carrying out a search on the Internet will return many results. Here are a list of some useful sites.
23andMe - http://www.23andme.com. Provide both genealogical and health related results.
AncestryDNA - http://dna.ancestry.com. Ancestry has possibly the largest and most widely used genealogical databases.
Family Tree DNA - https://www.familytreedna.com/.
African Ancestry - http://www.africanancestry.com/home/. Very popular with people of African decent in the west. They maintain a database of DNA samples from various Africa communities which can be used to match against.
The Genealogist DNA - https://www.thegenealogist.com/dna/.
Resources and further reading
Guide to DNA Testing: How to Identify Ancestors, Confirm Relationships, and Measure Ethnic Ancestry through DNA Testing by Richard Hill.
Finding Family: My Search for Roots and the Secrets in My DNA by Richard Hill.
DNA: Family History Genealogy and Ancestry Research Through DNA Testing (Genetic Testing, Family History Genealogy, Ancestry Research, Ancestor, Roots) by Martin Arrowsmith.