Principal component analysis of the degrees of impossibility of 43 species, for 28 core genes. Each point on the diagram corresponds to a species, and received the colours of its group, as indicated on the left of the graph. The two tables contain the results of the two statistical tests applied to the coordinates on axis 1 and on axis 2, to decide if a priori groups of points on the principal component analysis are overlapping or not. Eight groups were tested (see. Mat. and Meth.). When two groups were non-overlapping, we reported IMPO for impossible grouping on the table, and when we could not reject the null hypothesis that they overlap, we reported POSS. We indicated by an impo*, when one test only rejected a grouping.