You can safely skip this if it doesn’t interest you.
Our personal DNA is created by a combination of two half-sets made up from our parents’ DNA. These half-sets are called haplotypes. We combine one inherited haplotype from our father and one from our mother.
The Y-chromosome is passed on unchanged from father to son, and the mitochondrial DNA (mtDNA) is passed on by mothers to each child, though only female offspring pass it on.
Investigating these Y-chromosomes reveals that my first traceable ancestor, and yours, goes back a very long way. Between 300,000 and 150,000 years ago the common paternal ancestor of all of today’s men was born in Africa. Of course he was not the only male of his time, it is merely that only his lineage and his Y-chromosome survived to be passed down to all humans today – the first alpha-male. Of course the popular press promptly heralded him as the Y-chromosome Adam. This Adam was defined as bearing the A00 haplotype – a version only found in African populations. Yes, we are all descended from Africans!
In the meantime female evolution can be tracked through the mitochondria, located in a circular molecule with its own genome sequence of thirty-seven genes (not the Y-chromosome’s 46). Down the years mitochondria have mutated and tracking the major haplotypes allows geneticists to categorise.
This mitochondria investigation has shown that all current living human beings derive from an individual woman, inevitably referred to as the Mitochondrial Eve. She lived around 180,000 years ago in East Africa and handed on the L haplotype which is shared by every woman in the world today. Clearly this DNA Adam and Eve could never have met.