Fig. 2

Analysis of microbial a-diversity of four different types of tongue coating. A Rarefaction curve: the abscissa is the number of sequencing strips randomly selected from a sample, and the ordinate is the number of OTUs that can be constructed based on the number of sequencing strips, which is used to reflect the sequencing depth. Different samples are represented by curves of different colors. B Venn diagram of OTUs with four different tongue coatings.The Veen diagram depicts the number of OTUs specific and shared by each of the four tongue coatings TWF, TYF, YGF, and WGF. C and D Results of a-diversity analysis of four tongue coatings. C Simpson index; D Shannon index