To explain why we have a mitochondria, we have to go back about two billion years to a time when none of the complexity of life as we see it today existed.
If you're planning to become a parent, better lifestyle habits can reduce the risk of obesity in your children.
It's a landmark case but there are many unknowns.
Scientists thought they were closing in on one great new treatment but may have found another instead.
Human population groups worldwide are highly homogeneous genetically. They are in fact 99.5% similar and their anatomical features vary in an uncorrelated fashion over the landscape.