TED-Ed: What can DNA tests really tell us about our ancestry?

<p>Two sisters take the same DNA test. The results show that one sister is 10% French, the other 0%. Both sisters share the same two parents, and therefore the same set of ancestors. So how can one be 10% more French than the other? Tests like these rely on our DNA to answer questions about our ancestry, but DNA actually can&rsquo;t tell us everything. Prosanta Chakrabarty explores the accuracy of DNA tests.</p>