Selfish DNA has been defined as DNA "with no phenotypic expression whose only 'function' is survival within genomes." In the 13 October Science, [http://www.sciencemag.org/] Ogata et al. find what appears to be selfish DNA lodged in the middle of 19 genes of Rickettsia conorii [http://www.genomebiology.com/resolver.asp?PubMedID=9336669], an intracellular bacterium of ticks (Science 2000, 290:347-350). The repeats are palindromes that encode a mildly hydrophobic α helix surrounded by two extended or coil regions. This appears to be a non-functional module that has been inserted at the surface of a collection of unrelated proteins. Although the inserts probably do not provide a specific function, genetic drift from the original sequence could allow the evolution of new protein sequences, domains and functions.