Genetic Genealogy Case Study: Unraveling a Misattributed Parental Event

Genetic genealogy, with its intricate web of DNA matches and family trees, often unveils unexpected truths about our ancestry. This case study revolves around Mrs. L's journey, which began with perplexing DNA matches that did not align with her known family history. 

Initially, Mrs. L’s Ancestry tree traced her lineage through her grandfather, G. P. The documented evidence seemed solid—until DNA testing introduced a puzzle: matches bearing surnames completely unfamiliar to Mrs. L, some as close as first and second cousins. 

To navigate this genetic labyrinth, the first step was grouping Mrs. L’s matches based on her four sets of great-grandparents. This systematic approach revealed four distinct groups, each potentially representing a different ancestral line. Notably, matches from her maternal side aligned neatly with known family trees, confirming their genetic connections. 

However, the paternal side posed a greater challenge. Despite identifying two distinct groups, none of these matches fit into the established paternal lineage. Delving deeper into their attached family trees revealed a recurring surname: Williams. This discovery, predating the release of Ancestry’s Shared Matches Pro Tool, prompted meticulous scrutiny and the construction of interconnected "mini floating trees" within Mrs. L’s ancestry. 

The exploration of the "mini floating trees" guided us to two individuals: J. Williams and his father, S. Williams. With WATO Plus, we tested a few hypotheses to determine whether James was J. Williams' son by analyzing shared centimorgans with verified descendants of J. Williams and S. Willaims and even a descendant of S. Williams father, M. Williams, providing insights into the probability of their biological relationship. Moreover, it facilitated consideration of an alternative scenario where James might be the son of S. Williams, father of J. Williams. 

 

At this point, it became clear that J. Williams was most likely the father of James, and we were still very aware that there were no matches that had any connections to the P surname in their trees.  

The turning point came with the introduction of BanyanDNA and Ancestry’s Shared Matches Pro Tool. These tools enabled the creation of a comprehensive tree encompassing the Williams and Brooks families, crucially helping validate the hypothesis that James’s biological father was not G. P., but rather J. Williams. 

BanyanDNA’s validation feature proved invaluable, correcting assumptions about individuals' generational placements based on shared DNA matches. This level of detailed analysis, including how matches related to each other, clarified complex family dynamics that would have been challenging to discern solely through traditional genealogical methods. 

 

Ultimately, Mrs. L’s suspicions were confirmed: James Williams was indeed her biological ancestor. Family members, long aware of the possible connection but never openly acknowledged, finally acknowledged the truth—a testament to the complex interplay of familial secrets and shared histories. However, her grandfather will still always be her grandfather, even if not her biological grandfather.  

This case study underscores the evolving role of genetic genealogy in uncovering hidden familial relationships and correcting historical inaccuracies. Despite challenges posed by mismatches between genetic and documentary evidence, tools like BanyanDNA and Ancestry’s Shared Matches Pro Tool offer unprecedented opportunities for genealogists to reconstruct and validate intricate family trees affected by misattributed parental events. 

As genetic research advances, cases like Mrs. L's underscore the value of integrating DNA evidence with traditional genealogical approaches to reveal hidden ancestral truths. As we explore the complexities of our family histories and the genetic factors that define us, it's essential to acknowledge and honor those who have shaped our familial and cultural identities, even if not our biological ones. Their influence is just as pivotal in shaping who we are as those who have directly contributed to our genetic makeup, whether knowingly or unknowingly.