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A guide to using DNA tests results.
DNA test results can be used to confirm or deny an already established paper trail.
The confirmation that DNA can provide without a paper trail is when an autosomal match is around the 12%, 25% or 50% range, pointing to an overwhelming amount of overlap and a definite 1st or 2nd degree relation. There are exceptions but they involve a researched paper trail with a documented lineage.
Please note: A community that has a tendency to intermarry within the confines of the same community, at least for a few generations, will create a higher degree of match due to the same DNA being reintroduced into the same community, producing an estimated relationship degree that is closer that in reality.
Guidelines
- Living people must be cited anonymously to preserve privacy
- Use Geni projects as case studies, linked to this project, to discuss the evidence for DNA profile relationships
Case study project
- state the proposal
- add relevant profiles to project
- display anonymized Gedmatch data from one-to-many comparison tool (optional)
- show a chromosome overlap chart (can be snapshot)
- other tools and charts, as you use them
- draw a DNA tree in the project (can be snapshot)
- summarize the DNA evidence and suggest a conclusion
- submit paper trail evidence
- describe other possibly-relevant points (geography, naming patterns, associations …)
- summarize all evidence and suggest a conclusion
- invite peer review (geni members; comments from other sources such as Family Tree DNA group administrators, “search angels,” bloggers … more than welcome)
- assent / dissent described and geni tree linking strategy implemented
Case studies (most recent on top)
- DNA evidence for John Davis of Acton Turville
- DNA evidence for unknown daughter Armstrong
- DNA evidence for George Evans and Elizabeth Williams
- DNA evidence for Patrick Size and Bridget Carroll
- DNA evidence for William Mutton and Mary Parsons - St Clether
Diagram of descent for DNA test takers
References
- The Genetic Genealogist
- BanyanDNA “an upcoming software tool for building, visualizing, and analyzing complex genealogies.”
- “How to Write and Publish a Proof Argument with DNA Evidence” (November 8, 2020) < link >
- “DNA Case Studies in the NGSQ” - Google Sheets Document < link >
- Mills, Elizabeth Shown. “Testing the FAN Principle Against DNA: Zilphy (Watts) Price Cooksey Cooksey of Georgia and Mississippi.” National Genealogical Society Quarterly 102 (June 2014): 129–52. PDF download. Elizabeth Shown Mills. Historic Pathways. https://www.historicpathways.com/articles.html : [17 February 2024].
- “Using DNA Test Results to Confirm a Pedigree,” 20 October 2020 at Family Tree Webinars. < link >
- Create a chart with LucidChart < link >
- “painting/mapping your Chromosomes at DNAPainter. Requires a Subscription. You can do at least one map free.
- other tools at DNAPainter: Shared cM Project Tool; What Are the Odds? (WATO)
- Tables for those testing positive for Ahkenazi Jewish ethnicity: < link >
- A link to Lara's blog with those tables plus much more info and valuable links: < link >