DOI
10.1073/pnas.1203287109

Summary
The publication deal with the analysis of the prokaryotic communities developed with different species of sponges. The interplay was demonstrated to produce a convergent evolution at the functional level. A realistic model of differentiation and convergence is provided.

Relevance for Complex Systems Knowledge
This is a massive study of ecology in a well defined model, showing the importance of convergence, i.e. in the fact that microbes leaving in the same type of environment get similar functions, though through different evolutionary traces.

Point of Strength
Convergence and horizontal gene transfer are two key elements in the evolution of populations of microorganisms living in similar conditions and at strict contact. The former could be driven by similar selective forces, whereas the latter is based on the mechanisms of DNA exchange, independently of the reproduction. Interestingly, from an evolutionary viewpoint, both are factors of homoplasy that is considered a noise for the classic evolutionary theory based on vertical transfer, but are increasingly shown to be key elements of the microbial evolution.