BIASED METRICS. “However, cyanobacteria will also surely evolve differently from mycoplasmas or methanogens. What are our principled metrics for degrees of difference, and how are we sure that these are free of the sorts of eukaryocentric bias that we discuss in the next section? What is our metric for “richer evolutionary potential”.”
http://www.pnas.org/content/112/33/10278.full