Fig. 2

PCA analysis of metabolomics data from mature dates. a PC1 scores from DS1-bolon and DS1-sysX are highly concordant. b & c PC1 scores plotted against PC2 scores for DS1-bolon and DS2-mature respectively. The color of the circular symbols indicates the corresponding date sample country of production and follows the country-color code on the geographical map shown on the top of the figure. The square symbols were added to indicate the median PC1/PC2 coordinates per country and follow the same color code. Countries are denoted by their ISO Alpha-2 international code. The US unique date sample from the first collection has been omitted to keep the geographical map simple. PC1 scores have been negated so that the order of the countries follows that on the map (West/East left/right respectively). With both datasets, a significant association between PC1 scores and the country of production, expressed as an ordinal variable (refer to methods), was found. PC2 from both datasets showed no significant association