Bacteria can invert gene sequences

Bacteria have the capacity to flip sequences of their genes from back to front, which can generate two different proteins from a gene. For example, Bacteroides thetaiotaomicron has a gene, thiC, that it can invert. One way round, it encodes for an enzyme needed to make the vitamin thiamine. The other way, it encodes a truncated protein. This ability seems to give the bacteria a survival advantage in different conditions. Researchers engineered bacteria that were ‘locked’ to either express the forward or the inverted version of thiC and examined the survival of the two populations of bacteria when grown at different concentrations of thiamine. Under conditions of low thiamine, bacteria that expressed the forward version of thiC dominated; when thiamine was high, the bacteria that expressed the inverted version of thiC had an advantage.