Earlier, I brought up in a discussion with a friend the concept of Mitochondrial Eve. I tried to explain it based on my limited knowledge which was basically as follows: All mitochondria are passed down from mother to their offspring, if you keep tracing back the mother of every person alive then eventually they will converge on one common source. My friends reaction to this was pretty violent, saying people are idiots if they believe this and it's not possible (that's the nice way of putting what she said). She had a hard time believing that 1 woman could have a daughter and that daughter would have a daughter, and always end up having a daughter for thousands of years to modern times. I also have some questions so I was hoping someone could clear it up. 1. Is this absolutely 100% fact? Is there evidence? 2. Does that mean all women alive today have exactly the same mitochondria, and if they do, then how do we know that they came from one person? (if it's always all the same throughout history then how can we say it came from 1 person?) 3. If I have it wrong can you try and explain it to me? Thanks!