When DNA Proves What Documents Can’t: The O’Brien Family Discovery
How modern genetic science validated a 150-year-old probate document—and what it teaches us about complex genealogical research
1874 Queens County probate document mentioning "Uncle Patrick O'Brien in Newport, Kentucky" - the single historical reference that would take 150 years to validate
When Terrence O'Brien died suddenly in November 1874 at age 41, he left behind four orphaned children in Queens, New York. His second wife had died just six months earlier, leaving the three youngest children in need of guardians. Thomas Higgins became guardian for the two girls, Mary Ann and Elizabeth. A Mrs. Madden took guardianship of 18-month-old Miles Murtha Lawrence. The oldest child, James Henry, was sent to Uncle Patrick O'Bryan in Newport, Kentucky.
The probate records named this distant relative: "Uncle Patrick O'Brien in Newport, Kentucky."
But was this reference accurate? For five years, I searched for proof.
The Traditional Research Dead End
Everything suggested the connection might be real:
Terrence O'Brien:
Irish immigrant hotel proprietor in Jamaica, Queens
Born 1833
Died 1874, leaving orphaned children
Patrick O'Bryan:
Irish immigrant locomotive engineer in Newport, Kentucky
Born 1830
Living at the exact location mentioned in probate
The ages were right. The locations matched perfectly. Both were Irish immigrants who arrived in the 1840s-1850s.
But I couldn't prove they were brothers.
What I searched:
Irish civil registration and church records
U.S. census records (1850-1910)
Naturalization documents
Ship manifests
Cemetery records
Newspaper archives
Court documents
Land records
What I found: Nothing that definitively connected them.
The probate document stood alone—a single tantalizing reference with no supporting evidence.
The Obstacles
Several factors made traditional research impossible:
1. Surname Variations
New York recorded him as "O'Brien"
Kentucky recorded him as "O'Bryan"
Was this the same family or different families?
2. Geographic Separation
800+ miles between New York and Kentucky
Different communities, churches, jurisdictions
No evidence of contact or correspondence
3. Irish Famine-Era Documentation
Limited civil registration before 1864
Church records destroyed
Working-class emigrants with minimal paper trails
4. Common Surname
O'Brien/O'Bryan is extremely common in Irish immigration records
Without additional identifying information, connections are speculative
After five years, I had a compelling circumstantial case but no proof.
Enter DNA Science
In November 2023, three descendants of Terrence O'Brien tested their DNA:
Barbara O'Brien Hamall (great-granddaughter through son Miles Murtha Lawrence)
Michael O'Brien (Barbara's brother, identical twin)
Miles O'Brien (Barbara's brother, identical twin)
The hypothesis was clear: if Terrence and Patrick were brothers, these testers should match descendants of Patrick's documented children at the 3rd-4th cousin level (approximately 20-50 cM).
The March 2024 Breakthrough
When reviewing Barbara's DNA matches, I noticed a pattern.
Multiple matches with seemingly unrelated surnames—Kuptz, Nawrocki, Lyhan, Powell, Browne—all shared something unexpected:
Every single one traced ancestry to Campbell County, Kentucky in the 1870s.
When I built out their family trees, they all descended from the same couple:
Patrick O'Bryan (1830-1913) and Mary McNamara
The exact family from the 1870 Kentucky census.
The DNA Evidence
All three siblings matched multiple Kentucky descendants:
DNA match documentation showing triangulation across multiple descendant lines of Patrick O'Bryan's documented children
The identical twins (Michael and Miles) both matched at exactly 43 cM—providing built-in quality control that confirmed testing accuracy.
Why This Matters
The DNA evidence created an unbreakable triangulation pattern:
✓ Multiple descendant lines (through both of Patrick's documented children)
✓ Consistent cM ranges (20-49 cM as predicted)
✓ Three siblings all matching independently
✓ Identical twins showing identical results
✓ Geographic correlation (all Kentucky origins)
✓ Exact location match with probate document
The probability of this occurring by chance is essentially zero.
After 150 years, the 1874 probate document was scientifically validated.
The Remarkable Legacy
The story has particular poignancy because of Miles Murtha Lawrence O'Brien—the 18-month-old orphan mentioned in that 1874 probate document.
Miles carried genetic markers proving his father's brother relationship to Patrick O'Bryan. Those markers passed through:
His marriage to Margaret Egan
Their child
Their grandchildren: Barbara, Michael, and Miles
It took DNA testing of that orphaned infant's grandchildren, 150 years later, to prove the probate testimony accurate.
Lessons for Genealogists
1. DNA can validate when documents can't
Traditional research hit an absolute wall after five years. DNA testing provided definitive proof in three months.
2. Don't dismiss fragmentary evidence
That single probate reference seemed too thin to rely on. It turned out to be precisely accurate.
3. Surname variations are recording differences
The O'Brien/O'Bryan spelling difference represented how different jurisdictions standardized Irish surnames—not different families.
4. Test multiple family members
Having three siblings test (including identical twins) provided validation and quality control impossible with single testers.
5. Look for patterns
The breakthrough came from recognizing that multiple "unrelated" matches all pointed to the same Kentucky family.
6. Combine methodologies
DNA works best when built on thorough traditional research. I needed those five years of documentary work to understand what the DNA was telling me.
Both Brothers Died on November 21st
A final remarkable detail: both brothers died on November 21st—Terrence in 1874 (age 41) and Patrick in 1913 (age 83), exactly 39 years apart.
When Traditional Research Reaches Its Limits
Not every genealogical question can be answered with documents alone. When you encounter:
Surname variations across jurisdictions
Geographic separation between family branches
Famine-era Irish immigration gaps
Single documentary references without corroboration
Common surnames with limited identifying information
DNA testing combined with professional research methodology may be the only path to answers.
The O'Brien case demonstrates that with systematic research, appropriate DNA testing, and rigorous analysis, even 150-year-old mysteries can be definitively solved.
Learn More About This Research
View the complete case study:
Related: The Irish Immigrant's Hidden Fortune - Another perspective on the O'Brien family story
Have a similar complex case? Contact us
About this research: This project was conducted following Board for Certification of Genealogists (BCG) professional standards over seven years (2018-2025), combining traditional documentary research with modern DNA analysis.
Discover Your Family's Story
Every family has untold stories waiting to be uncovered. Let's reconstruct your ancestor's lived experience through rigorous archival research.
Start Your Research