So, now that you’ve sent a sample of your DNA to the testing company, what can you expect the results to tell you?
Will it prove that you’re descended from one of the 11th century kings of Ireland?
Will it prove that your fifth great-grandmother came from a particular village in Cameroon?
Will you be able to say, as Pooh-Bah said in Gilbert and Sullivan’s “The Mikado,” “I am, in point of fact, a particularly haughty and exclusive person, of pre-Adamite ancestral descent. You will understand this when I tell you that I can trace my ancestry back to a protoplasmal primordial atomic globule.”
The answer, unfortunately, is, “No.”
Some explanation is in order.
The science of genetics is a branch of biology that is concerned with genes and the way traits are inherited. The study of genetics has come a long way since the Moravian friar Gregor Mendel began experimenting with pea plants in 1856. The world of haplogroups and centimorgans and single-nucleotide polymorphisms is far more complicated than a short column can cover, but we can hit some of the high spots.
The tests done for genealogical research are Autosomal, Mitochondrial or mtDNA, and Y-Chromosome or Y-DNA. Each test looks at different parts of genes.
Autosomal testing looks at 22 of the 23 pairs of chromosomes, also called autosomes, which are not involved in determining a person’s gender. Each of us received exactly half of his or her autosomes from each parent. They are inherited roughly equally from grandparents through three-times great-grandparents. What we inherit from more distant generations is more random. This test reports how much DNA is shared by individuals, and therefore how closely they are related. It can also be used to estimate ethnicity.
The mitochondrion is a part of a human cell and has its own DNA. Mitochondrial DNA is transmitted directly from mother to child in the egg cell. A mitochondrial match indicates shared ancestry anywhere from one to 50 generations in the past.
Y-chromosomes are passed, unchanged, from father to son, meaning that Mr. Jones’s grandfather’s grandfather’s grandfather’s Y-chromosome will match his own. That also means that grandfather’s grandfather’s uncle will also have the same Y-chromosome, so a match does not necessarily indicate descent from a specific individual, but it does indicate that Mr. Jones and his great-great-uncle had a male ancestor in common.
Now, back to that sample you sent to the testing company.
A DNA test result is evidence that must be looked at in connection with other evidence, including evidence found in census records, deeds, wills, tax records, birth certificates, military pensions and all the other more traditional sources.
Genealogists traditionally rely on evidence from government documents, as well as such sources as private letters, church records, family Bibles and interviews with Great-aunt Sophie. DNA analysis is a relatively new form of genealogical evidence, and whether your research is for your own family history or for someone else’s, you will need to be familiar with some of the principles of genetic genealogy.
Dr. Blaine T. Bettinger writes, in his blog “The Genetic Genealogist”: “DNA is appropriately recognized as being an important aspect of genealogical research. Indeed, the modern genealogist who ignores DNA does so at their peril; beware a genealogist that intentionally ignores any potential source of evidence.”
Genetic genealogy can be defined as the use of DNA tests in combination with traditional genealogical methods to infer biological relationships between individuals.
In the past two decades, the science of DNA testing has advanced rapidly, and as a result, there are several companies offering direct-to-consumer DNA testing. Even beginners in the field of family history have heard of DNA tests done by Ancestry, Family Tree, My Heritage, and 23 and Me.
Television shows such as “Who Do You Think You Are?” “Long Lost Family” and “Finding your Roots with Henry Louis Gates Jr.” use DNA analysis as an integral part of their research.
For more detailed discussions of genetic genealogy, look for anything written by Blaine Bettinger. In addition to being a professional genealogist, he holds a doctorate in biology. He has authored several books on genetic genealogy, as well as a blog.
The Adamson Library is open by appointment only. To make an appointment, contact the Augusta Genealogical Society by email at AugustaGenSociety@comcast.net. Allow one week for a response to your request.
The Augusta Genealogical Society has two events coming up.
- The Following Footsteps to your Ancestors webinar series continues at 1 p.m. July 24 with “Newspapers: The Facebook of Today,” presented by Debra Brodowski.
- The 2021 Annual Genealogical Symposium “Researching Your Pennsylvania Heritage” featuring Elissa Scalise Powell, certified genealogist, will be held from 9 a.m. to 4 p.m. Aug. 7. For details and registration, go to augustagensociety.org.