3.1 Bacterial 16S rRNA sequence data
A total of 335455 raw reads were yielded from 8 samples. After quality filtering, 299149 valid reads were obtained, with an average of 37393 valid reads per sample remaining. All estimated Coverage values were over 99%, which indicated the current sequences sufficiently covered the diversity of the sample of bacterial communities (Table 1). Retained 268 OTUs, clustered at 97% sequence similarity, were detected in samples. Among them, 155 OTUs were shared between both sexes, 110 OTUs were specific in male, whereas only three OTUs were specific in female.