ScienceFocus.com

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

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.

Submitted by Rhiannon Buck

Mitochondria

Sat, 2010-06-26 18:51
Spacebeagle

The mitochondrian is an "organelle" that exists in most plant and animal cells.

It's the "powerhouse" that provides energy, in the form of ATP, for the plant or animal.

Interestingly, the mitochondrian seems to be the relic of a very ancient bacterium that invaded living cells billions of years ago. The "deal" was, I get stuff from you and I give you stuff in return.

Mitochondrial DNA is only passed from the mother to her offspring. It's totally different from the normal DNA found in human cells; it is, in fact a living "fossil" in the form of the DNA found in the original, invading bacterium.

What is really fascinating is that freeliving bacteria almost the same as mitochondria have been found.

In addition to mitochondria, most of the "organelles" found in modern day plant and animal cells seem to be descended from independent micro-organisms that were once separate.

Mindblowing and well worth doing a bit of reseach!