Hello and welcome to Four Letters Long. I am Ciara Nolan, I am a geneticist in Dublin, and for eight years I read people's genomes and tried to explain them back. This show is that job, but with you. Today we start with a listener from Cork who took two ancestry tests and got two different pie charts. She wants to know which one is lying. The answer is neither, and the reason tells you a lot about what these tests actually measure, which is not history but a comparison to living people who happened to join the reference panel. I will explain what the chip reads, why the percentages shift, and the one thing these tests are brilliant at, which is finding relatives you did not know you had. You are listening on Witspeak Podcasts. Let us open the envelope.