EXAMPLE OF ENDOSYMBIONT. “P. chromatophora “harbors photosynthetic endosymbionts derived from free-living cyanobacteria. The chromatophores are vertically transmitted and partitioned to offspring equitably. There is also substantial genomic integration between host and symbiont as a result of EGT and the invention of protein import machinery.” (P= Paulinella). (EGT = external gene transfer).
http://www.pnas.org/content/112/33/10278.full