Maybe you grew up with your biological family and you just want to know more about where they came from before they settled in the States. Maybe you were adopted and want to know more about your biological history. Maybe you never knew who one of your biological parents was because of an unusual circumstance. Whatever the reason, you want to know more about your family’s past and direct to consumer DNA testing can help to sort out fact from fiction. Please understand that when you undertake genetic testing you may find out things that are surprising or even upsetting to you or other people in your family. There’s a saying among the genetic genealogy community - “People lie, DNA doesn’t”. If you aren’t ready to confront possibly uncomfortable truths, direct to consumer DNA testing probably isn’t for you. But that being said, if you are ready to take the plunge and get some answers, here’s a step by step guide to how to begin to unravel your results.
Decide which company to test with.
There are several companies available for genetic testing for ancestry in the States. The largest three are Ancestry.com, 23andMe, FamilyTreeDNA and MyHeritage. If money is no object, I would recommend testing with all companies as they each approach ethnicity calculations a bit differently. However, if you are looking to match with previously unknown relatives and you have a small budget, Ancestry, by far, has the largest database. CeCe Moore runs a volunteer genetic genealogy group on Facebook called DNA Detectives and the group there has created a handy flowchart to help people navigate the decision-making process. I also made a slide presentation for my students last December to go over this process too.
Test and then upload your results to other sites to maximize matches.
Even if you only have enough money to order one DNA test, you can get the most bang for your buck by uploading your raw data to sites like GEDMatch, MyHeritage and FTDNA. You should never assume that your genetic relatives will definitely have chosen the same company to test that you have or that everyone who does DTC testing is aware of all these databases. So don’t get discouraged if it takes a while to find really useful matches. GEDMatch is a database that was created so that users who had tested across the different platforms could find genetic matches even if they didn’t use the same company to test. Plenty of other folks have raised concerns about the use of these databases by law enforcement to identify suspects or victims in cold cases so I won’t get into that here, but suffice it to say that all of these companies give you the option to prevent law enforcement from using your data.
Interpret your results.
This is the hardest part of the process if you are a genealogy newbie. First of all, please understand that all companies attempt to estimate the relationship between individuals in their databases by saying things like second cousin or third cousin. Many people don’t understand the terminology that genealogists use so that alone is confusing. Then on top of that, those estimates are often missing nuance that would actually help you figure out the relationship between you and your unknown matches. So to begin - let’s look at how to determine relationships.
Most people know that their first cousins are the children of their parents’ siblings. First cousins share a set of grandparents. People tend to get confused when they hear things like “second cousin twice removed”. When someone says removed, they are talking about differences in generations between the original person being studied (you) and their relative. So for example, the children of my first cousins are my first cousins once removed because I am the same generation as their parents. My cousins’ children are my children’s second cousins because they share a set of great grandparents. But don’t get too worried about this terminology just yet…
To sort out the genetic relationship between two people the most important thing to know is how much DNA they share. Humans typically* all have a total of 46 chromosomes or 23 pairs of large DNA segments. (*I say typically because some people have extra chromosomes as in the case of folks with Down syndrome.) We each inherit one set of 22 autosomes or non-sex determining chromsomes from each parent as well as one sex chromosome (X or Y) from each parent. Males get their X chromosome from their mothers and Y chromosomes from their father, while females inherit an X chromosome from each parent. Scientists measure DNA segments using a unit called centimorgans (cM), named for a famous fruit fly geneticist Thomas Hunt Morgan. The total amount of DNA you have among all 46 of your chromosomes is about 7400 cM. Since you inherited half your chromosomes from each parent, you will have about 3700 cM in common with them. The reason I say “about” is because sometimes the DTC labs don’t get complete coverage of the SNPs across your chromosomes so it may appear that you share a little less DNA. Thankfully, a lot of very smart people have been analyzing the data from DTC genetic testing over the past 10 years or so and there are several charts and tools to help you better understand the probability of a relationship between you and a newly discovered relative. I strongly encourage people to use the cM tool on DNA Painter.
The more closely related two individuals are, the more DNA they will share. Most folks don’t get lucky enough to find a lot of super close genetic matches right off the bat, but that’s OK. Remember that each person has 8 great grandparents and 16 great-great grandparents. If you know what you are doing, matches in the second and third cousin range - people who share those great or great-great grandparents with you - can answer most questions.
Now that you have some background knowledge, here’s where the real work of sorting out relatives can begin. It’s important to figure out what matches you have in common with your newly discovered relatives so that you can figure out who your shared common ancestor was. Genealogist Dana Leeds developed a simple visualization method using an Excel spreadsheet a few years ago - now called the Leeds method. You can use the same approach to compare matches across platforms or try out some of the online tools that have been developed to help cluster matches for you (Cluster Mapper or CLM).
Build a tree.
You will need a place to keep your research organized. Digital family trees are the way to go. I use Ancestry.com to house my tree (which has over 14k people in it after more than 20 years of research), but that’s not free. You can also set up free family trees and search a ton of records on FamilySearch, the genealogy site created by the Mormon church. MyHeritage also hosts family trees. If you have money but don’t have the time or energy to develop the tree yourself, you could look into hiring a genealogist to do it for you. There are quite a few helpful tutorials available on YouTube to give you an idea of how to start building trees incorporating your genetic matches (Building Quick & Dirty Trees to Identify Genetic Matches, How to Create a Floating Tree and Merge Duplicates on Ancestry.com, Next Steps For Using DNA to Find Unknown Ancestors or Parents of Adoptees).
Don’t get discouraged.
It takes a lot of time and effort to sort out some family mysteries. Sometimes you just don’t have enough decent matches to answer the question you have. Other times, you may find that people don’t want to talk to you about their family or your shared ancestor - especially if it means uncovering an affair that resulted in a child. When in doubt, ask someone with more experience to check your work. Be patient and stay positive. You may not get the answers today, but that doesn’t mean you won’t have them down the road. Best of luck to you and happy hunting!
No comments:
Post a Comment