Fecal microbial signatures of healthy Han individuals from three bio-geographical zones in Guangdong

Abstract

Important forensic evidence traced from crime scenes, such as fecal materials, can help in the forensic investigation of criminal cases. Intestines are the largest microbial pool in the human body whose microbial community is considered to be the human "second fingerprint". The present study explored the potential for community characteristics of gut microbes in forensic medicine. Fecal microbiota profiles of healthy individuals from three representative Han populations (Guangzhou, Shantou and Meizhou) in Guangdong Province, China were evaluated using High-throughput sequencing of V3-V4 hypervariable regions of the 16SrRNA gene. Results of the present study showed that at the genus level, Shantou, Guangzhou, and Meizhou behaved as Enterotype1, Enterotype2, and Enterotype3, which were mainly composed of Bacteroides, Prevotella, and Blautia, respectively. Based on OTU abundance at the genus level, using the random forest prediction model, it was found that there might be potential for distinguishing individuals of Guangzhou, Meizhou, and Shantou according to their fecal microbial community. Moreover, the findings of the microbial community of fecal samples in the present study were significantly different from that of saliva samples reported in our previous study, and thus it is evident that the saliva and feces can be distinguished. In conclusion, this study reported the fecal microbial signature of three Han populations, which may provide basic data for the potential application in forensic practice, containing body fluid identification, and geographical inference.

Keywords: 16S rRNA gene sequencing; Guangdong Han individuals; feces; forensic medicine; gut microbiome.

Figure 1

Venn diagrams of bacterial OTUs in all fecal samples from people in Guangzhou, Meizhou and Shantou.

Figure 2

Differences in bacterial alpha diversity among the three regions: (A,E) Chao. (B,F) Ace. (C,G) Simpson diversity. (D,H) Shannon index.

Figure 3

Distribution of intestinal microbes at different taxonomic levels in Guangzhou, Meizhou and Shantou populations. Two levels of dominant taxa are shown (Others: <0.5% relative abundance). (A) Distribution at the phylum level. (B) Distribution at the genus level.

Figure 4

Taxonomic diversity of microbiomes from samples from Guangzhou, Meizhou, and Shantou. The principal coordinate analysis (PCoA) graph analysis is based on the Bray-Curtis distance at the operational classification unit (OTU) level, and each sample is represented by a point. (A) Guangzhou vs. Meizhou. (B) Shantou vs. Meizhou. (C) Guangzhou vs. Shantou. (D) Guangzhou vs. Shantou vs. Meizhou.

Figure 5

Differentially abundant taxa between the three regions. These different genera from phylum to genus were identified by linear discriminant analysis (LDA) using LEfSe. (A) Cladogram result graph. (B) Linear discriminant analysis (LDA) value distribution histogram. Red: Guangzhou; green: Meizhou; blue: Shantou.

Figure 6

Receiver operating characteristic (ROC) curves trained on the OTU abundance demonstrate the performance of distinguishing fecal samples from Guangzhou, Shantou, and Meizhou. Yellow line: Guangzhou; blue line: Shantou; and green line: Meizhou.