DNA testing brings a new tool to genealogy with the ability to match your genetic material or genome to your cousins. DNA testing is a broad term with three types of testing available to genealogists. Each test provides different information.
Mitochondrial DNA (mtDNA) was the first test available to genealogists. The mitochondrion is the power plant for each cell in your body and has its own DNA, separate from your cellular DNA. mtDNA is inherited from your mother. Men and women each have mtDNA, but men do not pass it on to their children.
mtDNA does not mutate very often and is used to find maternal origins as it is traced from a daughter to her mother, to her mother, to her mother back to ancient times. The basic use of mtDNA is to exclude someone from your direct maternal lineage. Both men and women can be tested for mtDNA, but only women pass it on to their children.
When I first had mtDNA testing performed, I spent hours emailing over 50 identical matches from all over the world. I was not able to match any common ancestors in my family tree. I could just confirm my Haplogroup U5a European/North African/India/Central Asia maternal ancestor had many descendants in Europe, the United States, Australia and New Zealand.
Each of us (with exceptions) has forty-six chromosomes, which pair up. Females have two X chromosomes and men have one X and one Y chromosome. The Y chromosome is passed down through the male lineage. The Y chromosome can be traced from a son, to his father, to his father, to his father, back many generations, but with mutations. Specific families can be identified as a result of the mutations. Only men can be tested for Y-DNA, since women have no Y chromosome. It was very exciting when the matches on my father’s Y-DNA test confirmed our Musgrove/Musgrave paper trail going back ten generations. This test is very useful when you can follow a direct male line.
The most recent DNA test available to genealogists is autosomal DNA testing, where portions of 22 pairs of chromosomes (all except X and Y) are tested. Within five to six generations, this test can find cousins who have had the same testing performed. Both men and women can take part in this testing.
I had my autosomal DNA testing performed through Ancestry.com and have matched five cousins with confirmed family ties and with about one hundred other people with no identified common ancestor. One recent match looks like it may clarify that the mother of my 3rd great grandmother was the second wife of John “Go Back” Eoff, rather than the first wife as indicated by some genealogists. That same day, a match showed up on another family line – one where I had entered my “best guess” ancestor on my Ancestry.com family tree. (Bad girl.) That Pennington line is an interesting Puritan family, where I do have documentation back several generations. Based on my new-found cousin’s research, I can collaborate with her when I do start working on documentation of that complete line.
The three major websites (Family Tree DNA, 23andMe, and Ancestry.com) are password protected and state their genomic data is secure. Other genealogical research sites allow people to download their own genome to allow open study for matching with other genomes. GEDmatch is one of the largest sites for open study. Recent DNA genealogy workshops I’ve taken have indicated GEDmatch is a safe site to load results for matching DNA to a broader community. That site has seen a lot of activity with Ancestry.com making DNA testing through their company available for download into other programs. GEDmatch has closed for new downloads through until August, while they process the current matches. I plan on downloading my own DNA results into GEDmatch after it reopens.
Since some gene sequences are tied to diseases and other personal characteristics, one could see a situation where, perhaps, health care providers or employers might consider mining such data for nefarious reasons. At this point, it looks like when genomic data is maintained within the testing site, privacy is maintained. Legislation is underway to prevent discrimination based on any genetic results.
I have downloaded my Ancestry.com results into FTDNA, the site where my parents and sister were tested. With our results on one site, I’ll be able to go to specific chromosomes and see which genes were inherited from which parents. I’ll also be able to see specific gene matches for cousins, helping pinpoint our common ancestor. This could help find a common ancestor for future DNA matches but with no common paper trail.
The cost of DNA testing for genealogy purposes has dropped dramatically with 23andMe offering the autosomal test for $99. However, at this point, I prefer testing on Family Tree. I’ll just see which relatives will agree to testing and wait for another sale on Family Tree.
If you test three siblings in each family with autosomal DNA, this would capture almost all the full genome of their parents. The earliest generation you have should be tested so, as my mother put it very well “you don’t dilute the DNA.” So over time, as I have funds available, I’d love to test two more of her siblings and two more of my dad’s siblings, along with some specific people for Y-DNA and mt-DNA.
I have a B.S. degree in medical technology and worked in a hospital laboratory. After receiving my master’s degree, I managed commercial laboratories for many years. That science background is helpful to me in studying the rapidly changing field of genealogical DNA testing.
Copyright 2013 by Andrea Musgrove Perisho.