
Why do mitochondria have their own genome?
Mitochondria are tiny chemical factories inside our cells, but the reason their blueprints are a bit different is down to bacteria.
Asked by: Caroline Ellis, Edinburgh
Mitochondria are tiny chemical factories inside our cells. They have several roles, including extracting and storing energy from digested food. But they also have their own DNA, hinting at a once-independent existence. It’s thought that this reflects their origin as bacteria, which formed a symbiotic relationship with organisms about 2.4 billion years ago and then evolved into us.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
Authors

Robert is a science writer and visiting professor of science at Aston University.
Sponsored Deals

May Half Price Sale
- Save up to 52% when you subscribe to BBC Science Focus Magazine.
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.
- Stay up to date with the latest developments in the worlds of science and technology.