
Why don’t all humans have the same blood type?
There is an evolutionary reason for having more than one blood type, and humans aren't the only species with such a trait.
Asked by: Margaret Hutt, Buckinghamshire
Our distant ancestors used to, but then mutations created different antigens on the outside of red blood cells, leading to the different blood groups. The first of these is thought to have occurred before chimpanzees and humans diverged, about 13 million years ago, creating blood group A; others are more recent. There are now 30 blood groups recognised and their proportions differ in different ethnic groups.
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
Sponsored Deals
Subscription offer
Subscribe and try your first 3 issues for just £5. After your introductory period you will pay just £22.99 every 6 issues by Direct Debit. Receive every issue delivered direct to your door with FREE UK delivery.