Of the thousands of bacteria swimming inside you, relatively few are bent on destruction. Most busy themselves in a communal effort to keep you fit and free from disease – unless something changes.
Scientists have long wondered what causes harmful bacteria to cross the species barrier from animals to humans and what causes a good bacterium inside us to turn bad.
Now, researchers at the University of Wisconsin-Madison have discovered that a single gene can cause bacteria to change hosts. Light-emitting bacteria called Vibrio fischeri colonized pinecone fish, then jumped to the bobtail squid – all because of a regulatory gene, the scientists reported Sunday in the journal Nature.