Geographic Ancestry Analysis

Ancestry Composition: 23andMe's State-of-the-Art Geographic Ancestry Analysis

Ancestry Composition is a powerful, well-tested system for analyzing your ancestry based on your DNA. We believe it sets a new standard in the industry for rigor. Here we'll try to explain how the analysis works in an accessible way, and present some key test results. If you have questions, please post a question in the 23andMe Community. You might also like to check out our more technical ASHG poster on the system.

Basics

All DNA ancestry analyses rely on the same signal to produce their results — they differ only in how they go about capturing this signal. The signal that they use is the association between a DNA marker and a geographic location. DNA markers vary widely in how strongly they are associated with a geographic location.

Here's an example to illustrate the idea. This image shows the frequency of the maternal haplogroup H around the world. You can see that H is very common in Europe, is found in Africa and Asia, and never seen in Australia or the Americas./.../