Humans have been blamed for the disappearance of species before but never quite like this. Scientists at the University of Oxford have found evidence that two species of bacteria are merging into one. The two species are swapping genetic material at such a high rate that they are on the road to sharing a single, common genome. Their genetic merger is probably the result of being thrust into a new environment – the intestines of heavily farmed chickens, cattle and other domesticated livestock.

The two bacteria in question – Campylobacter jejuni and Campylobacter coli – are two of the most common causes of gastroenteritis, or food poisoning, in the world. They infect a broad range of animals including mammals, birds