Something borrowed, something green: lateral transfer of chloroplasts by secondary endosymbiosis.

New molecular data confirm what electron microscopists long suspected - fusion of two different eukaryotic cells into a single more-complex cell created novel groups of protists. By engulfing an algal cell and putting it to work as a solar-powered food factory, heterotrophic protozoans became autotrophic. Drastically reduced, the engulfed cell now exists as an organelle in the host cell. Such blending of lineages was perhaps a driving force in early eukaryotic diversification.