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DNA Day at the FamilySearch Library (view source)
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==''Using DNA to Find Unknown Parents: A Case Study''== | ==''Using DNA to Find Unknown Parents: A Case Study''== | ||
Identifying unknown parents can be solved using a combination of sound, genealogical research coupled with DNA testing. To do so, follow these steps. The case study for this presentation was done entirely using Ancestry DNA matches, but you can apply the same principles using other DNA companies. | |||
'''Take a DNA test with a company that provides information about DNA matches''' | |||
There are five companies that provide DNA match lists: | |||
*Ancestry | |||
*MyHeritage | |||
*Family Tree | |||
*23andMe | |||
*Living DNA | |||
For maximum results, seriously consider testing with every company. You never know which company will list the closest match that can solve the problem. | |||
'''Identify and isolate matches''' | |||
Matches are listed in order by the amount of DNA they share with you. This is measured in '''centiMorgans (cM'''). When possible, identify who the person is and how that person is biologically related to you. Be exact with your relationship and note if the person is a half-relation (half-sibling, half-nephew, etc.) | |||
Use the tool [https://dnapainter.com/tools/sharedcmv4 '''DNA Painter: Shared centiMorgan project'''] to identify possible relationships between you and your match. DNA Painter will show any possible relationships, as well as how likely those relationships are. Any other relationship is virtually impossible, unless you are related multiple times to the match.<br> | |||
When isolating matches, if possible, identify a known relative who only shares a ''portion'' of your ancestors. For example, a grandchild would not be a good place to start, but a half-sibling would be. Identify all shared matches with that person and make sure to clearly label them. You can then label the individuals you do ''not'' share matches with, as from a different branch of the family. The best practice is to isolate paternal from maternal matches, working backwards one generation at a time. In the case of unknown parents, creating clusters of individuals that share matches with each other, even when the parent is unidentified, is essential to creating a list of potential candidates for the parent. | |||
'''Build trees for your matches''' | |||
Next, build a common tree for each cluster of matches. First, look at all available family trees for each match (not every match will have a tree). In those available trees, look for any shared surnames. If there are no shared surnames, look for any shared locations. Keep in mind that if a match's tree is not far enough back to identify shared surnames, you may have to do some genealogical research to extend a tree until you come across the surname.<br> | |||
Once a likely ancestral couple or ancestor is identified, track ''all'' descendants of that couple forward until the time the person with the unknown parents was born. Then, identify all potential candidates for the parent. Then, use tool [https://dnapainter.com/tools/wato '''DNA Painter: What Are the Odds?'''] to plot out the descent of each of your matches in the cluster to the ancestor or ancestral couple. Be sure to enter how many centiMorgans you share, as well as birth years of each generation. Then, use suggested hypotheses to identify the most likely place for the person with unknown parents to be in the family tree. | |||
Keep in mind that candidates should be alive, of childbearing age, and ideally living in the same area (particularly for unknown mothers) as the birth of the person. | |||
'''Craft a Theory''' | |||
In the What Are the Odds tool, each score is based on how likely the person fits in that position in the tree. Rank the highest scores in the list, and focus on those relationships first. Identify potential candidates in those spots. | |||
'''Confirm your Theory''' | |||
Once a potential candidate is identified, you can then confirm (or debunk) your theory by eliminating any candidates based on age, location, or other reasons and contacting matches without trees to identify their specific relationship to the target ancestor. If possible, you can identify key people to submit a DNA test that can help verify or disprove a candidate (the closer a relationship to the candidate, the better). Keep using the DNA Painter tools Shared cM Project and What Are the Odds to identify possible genetic relationships and refine your hypotheses. | |||
===Additional Resources=== | ===Additional Resources=== | ||