Fig. 1From: Absolute quantitation of microbiota abundance in environmental samplesSynthetic spike design. P, E and F synthetic spikes were designed using PBS sequences, together with the length and GC content of amplicons from prokaryotes (P), eukaryotes (E) and fungi (F), respectively. For P synthetic spikes the primer binding sites (PBS) shown in orange, for E in green and for F in blueBack to article page