title: 16S rRNA V3-V4 amplicon sequencing of Equus caballus uterine cytobrush
design: A combination of 8 forward (TSD501-508) and 4 reverse indexing primers (Amp_N714, 715, 716, 718) was used for the 28 samples. After barcoding, PCR products were purified using 0.8x magnetic beads (Sera-Mag Select Beads, Cytiva, Marlborough, USA). The quality and quantity of the resulting libraries were assessed using the 4200 TapeStation system (Agilent Technologies). Libraries were normalized to a concentration of 10 nM in Tris-HCl (10 mM, pH 8.5, 0.1% Tween 20) and pooled in equimolar amounts before 2 x 300 bp paired-end sequencing on an Illumina NextSeq2000 instrument according to standard protocols.