Family Trees Don't Grow Forever
As you go back in time, family lines don't keep branching.
They begin to meet.
Pedigree collapse is not an anomaly. It's how ancestry actually works—a natural reflection of shared human history, community continuity, and the mathematical reality of finite populations.
What Is Pedigree Collapse?
A simple truth about how ancestry works
Pedigree collapse occurs when the same ancestor appears multiple times in your family tree. It is inevitable in any population with limited size, and it becomes more common the further back you go.
This isn't unusual. It's how ancestry actually works.
Understanding the Math
Go back 10 generations, and you theoretically have 1,024 ancestors. Go back 20 generations, and that number becomes over one million. Go back 30 generations—over one billion.
But here's the reality: there weren't one billion people alive 30 generations ago. The math only works because the same people appear multiple times in your tree. Your ancestors loop back on themselves.
Why Pedigree Collapse Happens
The human story behind ancestral convergence
Small Historical Populations
For most of human history, populations were small. Villages had hundreds, not thousands, of people. Finding a spouse often meant marrying someone who shared distant ancestors.
Geographic Proximity
Before modern transportation, most people lived and married within a few miles of where they were born. Communities stayed connected across generations.
Community-Based Marriage
People married within their faith, culture, profession, or social class. These patterns meant the same families intermarried repeatedly over centuries.
Mathematical Reality
The number of theoretical ancestors doubles each generation, quickly exceeding the actual historical population. Overlap isn't just possible—it's mathematically inevitable.
Pedigree collapse reflects how communities persisted over time—not isolation, but connection. It is the natural result of people living, working, and building families together.
What Pedigree Collapse Really Means
Reframing convergence as connection
It Does Not Reduce the Richness of Your Ancestry
Having ancestors appear multiple times doesn't mean your heritage is less diverse. It means your lineages are more deeply rooted in specific communities and places.
It Does Not Imply Recent Relatedness
Pedigree collapse typically occurs many generations back. It reflects patterns from centuries ago, not your immediate family.
It Reflects Shared Human History
Every person alive today carries the legacy of overlapping lineages. Pedigree collapse is evidence of our common humanity, not a limitation.
Pedigree collapse doesn't shrink your ancestry.
It reveals how connected people were.
What This Report Reveals
Not who you're missing—but how people came together
Where Lines Converge
See which ancestral paths meet and at what generational depth. Understand the structure of your family tree beyond the theoretical model.
Repetition at Different Depths
Discover how often ancestor repetition appears as you go back in time. Most collapse occurs beyond 6-8 generations, where it becomes universal.
Population History Insights
Learn what your pedigree collapse patterns reveal about the historical populations your ancient matches belonged to—geographic and cultural continuity.
Coefficient Analysis
Receive a pedigree collapse coefficient that quantifies the degree of ancestral overlap, explained in clear, accessible terms.
Historical Context
Understand how your results compare to historical and population-wide patterns. Context transforms numbers into meaning.
Family Perspective
Gain insight into how your family's history fits within broader demographic patterns of community, migration, and continuity.
Reading Your Results Correctly
What to expect and how to understand it
Before you view your report, it's important to understand what pedigree collapse results mean—and what they don't mean. This section helps you interpret your findings with perspective.
Pedigree Collapse Increases Naturally With Time
The further back you go, the more collapse you'll see. This is expected and universal. At 10+ generations, virtually everyone shows significant overlap.
Everyone Has It
There is no family tree without pedigree collapse. If you go back far enough, every person's tree converges. This is a mathematical certainty, not an exception.
It Does Not Imply Recent Relatedness
Finding pedigree collapse in your results says nothing about your parents or grandparents. The patterns reflect historical populations, often centuries in the past.
It Carries No Personal or Cultural Judgment
Pedigree collapse is a neutral demographic fact. It reflects history, not character. Every population on Earth shows these patterns.
Your results are presented with context and care. We designed this report to inform and reassure— never to alarm or sensationalize.
The Science Behind the Analysis
This is not speculation—it's arithmetic applied to history
Genealogical Mathematics
The number of ancestors doubles each generation: 2 parents, 4 grandparents, 8 great-grandparents. By generation 20, you'd need over 1 million unique individuals—but they didn't exist.
Population Size Effects
Historical populations were far smaller than today. Medieval Europe had perhaps 60-80 million people; earlier periods had even fewer. Limited population means shared ancestors.
Pedigree vs. Genetic Relatedness
Pedigree collapse measures how often ancestors appear multiple times in your tree. This is different from genetic similarity, which depends on which DNA segments were actually inherited.
How We Calculate Your Report
Analyze runs of homozygosity (ROH) in your DNA data
Compare patterns against population reference panels
Estimate ancestral overlap across generational depths
Provide context with historical population data
See How Your Lines Converge
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Pedigree Collapse Analysis
- Pedigree Collapse Coefficient
- Generational Depth Analysis
- Population Comparison
- Historical Context
- Clear Explanations
- Instant Digital Access
Your data stays private — GDPR compliant
Frequently Asked Questions
No. While both involve shared ancestors, pedigree collapse is a universal phenomenon that occurs in every family tree going back enough generations. It reflects normal demographic patterns over centuries, not recent family relationships. Everyone alive today has pedigree collapse in their ancestry—it's a mathematical certainty, not an exception.
Not in any meaningful recent sense. Everyone's parents share ancestors if you go back far enough—this is simply how human population history works. Pedigree collapse in your report reflects patterns from many generations ago, typically before your great-great-grandparents' time.
No. Pedigree collapse is a neutral demographic observation, not a health concern or personal judgment. It tells you about historical population patterns, not about you personally. Our report is designed to inform and provide perspective, not to alarm.
Our analysis uses established genetic methods including runs of homozygosity (ROH) detection and population genetics modeling. The results reflect genuine patterns in your DNA, interpreted through the lens of population history. We provide confidence intervals and context to help you understand what the numbers mean.
We accept raw DNA files from 23andMe, AncestryDNA, MyHeritage, FamilyTreeDNA, Living DNA, and most other standard testing companies. Whole genome sequencing (WGS) files also work. Simply upload your file after creating a free account.
We believe everyone deserves to understand their ancestry without barriers. The Pedigree Collapse Analysis is offered as a free educational tool, helping people learn about this fundamental aspect of genealogy and population genetics.
Pedigree collapse doesn't tell you how small your world was.
It shows how connected it has always been.
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