Fig. 6

Concepts of the phylogenetic informativeness of gene families and the limits of ortholog detection. As lineages diversify (top), the rate of evolution of each lineage impacts the phylogenetic informativeness (PI) of each gene (bottom). In the case of gene families that exhibit relatively slower rates of sequence evolution, phylogenetic information content may continue to accrue over time, thereby increasing the amount of information available for inquiry (blue). In contrast, rapidly evolving loci can exhibit serial substitutions at the same site that erode phylogenetic information (red). The ability to resolve the evolutionary history of such “saturated” loci can be limited