Fig. 1.

Inferring the diversity of plant items consumed in the past using a DNA-based crystal ball. Plant items consumed 12 to 48 h before stool samples are collected are represented in stool-derived DNA. The crystal ball looks into the past by converting highly variable DNA samples into consumed plant diversity measures. DNA found in human feces contains mostly nonplant DNA, but in this study, it is shown that “fishing out” the trnL gene using a molecular technique called PCR and then sequencing the amplified DNA are sufficient to infer consumed plant diversity measures that correlate well with “gold standard” nutritional epidemiology questionnaire-based data.