YOU ARE NOT A GENEALOGIST UNTIL YOU KNOW THESE 5 DNA TRUTHS

You are not a genealogist until you know these 5 DNA truths — and the first costs people the most. A match at 1,800 shared centimorgans can be your grandparent, your aunt, or your half-sibling, and the test cannot tell you which. People find siblings this way. People find out who their father wasn't this way. Here are the five things that govern what these tests can and cannot do. None are secret, and almost nobody who buys a kit is told any of them. QUESTIONS THIS VIDEO ANSWERS • What does 1,800 centimorgans mean — grandparent, aunt, or half-sibling? • Why do my siblings get different ethnicity results? • Why did my ethnicity estimate change after an update? • Why do I have thousands of close matches I can't place? TRUTH ONE: THE RELATIONSHIP LABEL IS A GUESS. Blaine Bettinger collected shared centimorgan figures from people who already knew how they were related, and the ranges overlap almost completely. Grandparent to grandchild, roughly 1,156 to 2,311 cM. Aunt or uncle, 1,349 to 2,175. Half siblings, 1,317 to 2,312. So 1,800 lands inside all three. What separates them is the figure nobody reads: the segment count. 1,530 cM across 26 segments looks like a grandparent. 1,756 across 51 looks like an aunt. Every generation of separation cuts the material into more and smaller pieces. TRUTH TWO: YOU CARRY NOTHING FROM MOST OF YOUR ANCESTORS. Nine generations back you have 512 ancestors on paper. On one side that's 256 people, and the number of separate inherited stretches you carry from all of them is around 286. Roughly one each, meaning many contributed nothing. They are your ancestors, you descend from them, and there is no trace of them in you. The split begins around six generations back. So when a test can't find a documented ancestor, sometimes she wasn't there — and sometimes she was and gave you nothing, and the test cannot tell those apart. TRUTH THREE: THE PIE CHART IS THE PACKAGING. Ethnicity percentages are not measurements of you. They are comparisons against a reference collection, and when the company changes that collection your heritage changes overnight. Every major company has rewritten its customers' percentages more than once. The cleanest proof costs nothing: compare with a full sibling. You won't match. Identical ancestry, identical tree, different numbers. The match list is the instrument; the pie chart is the box. TRUTH FOUR: TWO THREADS OUT OF HUNDREDS. The paternal-line and maternal-line tests follow one male chain and one female chain. Nine generations back that is two ancestors out of 512. And the male line breaks on a single event anywhere along it: one adoption, one remarriage, one child born to another father, and you are following a different family than your paperwork says. Four hundred years of Flemish records put that near one to two percent per generation — far below the folklore figure of a third, but compounding across ten. TRUTH FIVE: IF YOUR FAMILY MARRIED CLOSE, EVERYTHING ABOVE BENDS. Appalachian valleys, Cajun Louisiana, island communities — any population isolated by geography, language or religion. When cousins marry cousins across generations the same ancestors fill several slots in your tree, you share with matches through multiple lines at once, and totals come out high with predictions far too close. A second cousin may be a fourth cousin twice over. The labels were built for families who married strangers. WHAT TO ACTUALLY DO. Use the match list, not the percentages. Read segment counts. Treat every relationship label as a question. And if either parent is living, test them before anyone else — their results cut your tree cleanly in half, and that window closes. CHAPTERS 0:00 A Name You Have Never Heard Of 1:26 One: The Relationship Is a Guess 3:12 Two: Most Ancestors Gave You Nothing 5:16 Three: The Pie Chart Is the Packaging 7:12 Four: Two Threads Out of Hundreds 9:18 Five: If Your Family Married Close 11:29 Test Your Parents First 13:02 Back to the Name on the List WATCH NEXT What DNA Revealed About the Cherokee Grandmother What Your Blood Type Says About Your Ancestors Why Millions of White Americans Carry African DNA Which of the five did you already know, and which is new? And if a result ever made no sense to you — a match too close, a percentage that moved, a line that vanished — tell me what it was. It is almost always one of these five underneath. #Genealogy #DNA #AncestryDNA #FamilyHistory #DNATesting #Centimorgans #AmericanBloodlines