This so-called ‘out of Africa’ theory is the topic of Oxford University paediatrician and researcher Stephen Oppenheimer’s new book, Out of Africa’s Eden. Its basis is the recent advances in genetics that allow the construction of gene lines, on the one side through mitochondrial DNA, which is inherited maternally (hence the origin of the ‘mitochondrial Eve’, the ‘first mother’ from whom we are all supposedly descended), and on the other through Y chromosomes, which are inherited by men.