Fig. 4

Presence and extraction efficiency of all HVR in the sequences of the DAIRYdb. Single HVR (a) and (b) and HVR pairs (c) and (d) HVRs were extracted using in silio PCR with mothur (b) and (d) and HVR extraction with V-Xtractor (a) and (b) from sequences present in DAIRYdb v1.1 to test completeness of the sequences therein. While almost 100% of the 10’290 sequences span over V2 to V8 only 89% contain V1 and 68% contain V9 (a) and (c). The in silico PCR highlights the theoretical amplification efficiency of the most common universal primers with 0 mismatches normalized to the total number of detected HVR (b) and (d)