Extended Data Fig. 2: Summary of the method used to estimate the B-vitamin profiles of nutritionally unknown species.
From: Global plant diversity as a reservoir of micronutrients for humanity
1) The branches of the phylogenetic tree are rescaled (often resulting in shortening internal branches relative to terminal branches, as in the second tree), so that the B-vitamin profiles of the nutritionally known species match the distribution expected under a Brownian-motion model. The parameter λ is used for this rescaling and represents the strength of phylogenetic signal for a given B vitamin, with values close to 1 suggesting strong signal64. The parameter σ2 is the estimated variance of the Brownian-motion process for a given nutrient. 2) The B-vitamin concentrations of the most recent common ancestors are estimated using the fastAnc function from “phytools”65, data for nutritionally known species, and the rescaled phylogeny. 3) The B-vitamin concentrations for nutritionally unknown edible species (here represented by “?”) are approximated as the values of the most recent common ancestors between the nutritionally unknown species and its most closely related nutritionally known species. The standard deviation (SD) of the prediction is calculated as the product of the variance of the Brownian-motion (σ2) and the branch length of the nutritionally unknown species to its most recent common ancestor with a nutritionally known species (t). CI refers to confidence intervals.
