Is there one gene that dates back to a single male ancestor

22nd July 2009

Asked by: Hannah Rowe, Bristol

There are both. The man lived about 60,000 years ago, the woman around 140,000 years ago. We know about them because a proportion of our DNA is passed on from generation to generation. In males, it is the DNA contained in the Y-chromosome, passed from father to son. In women, the DNA is contained in the mitochondria – the ‘powerhouses’ of cells – and passed from mothers to daughters, but not to sons. In 1987 scientists from the University of California at Berkeley studied the mitochondrial DNA from 147 people, drawn from five different geographic populations. All samples arose from a common ancestor, ‘Mitochondrial Eve’. She was one of a group of about 10,000 people living in Africa, but the mitochondrial DNA of all the other women is gone because at some stage in the line of descent only sons were born. ‘Y-chromosomal Adam’ was identified in 2002 by Spencer Wells, leader of The Genographic Project.