Preliminary study on characterization of gut microbiota and individual tracing in migratory populations

DNA profiling is widely used in forensic individual identification. Yet, traditional forensic methods fail to determine the short - or long - term residence of migrant populations, imposing challenges in tracking these populations. Intestinal microorganisms can differentiate people across various geographical locations. Nevertheless, there's a lack of detailed exploration regarding the microbial changes and structural composition of migratory groups. To characterize migration routes and identify migratory groups via microbial composition, we conducted 16S rRNA sequencing on intestinal microorganisms from 50 Chinese and 131 Africans who migrated to China. Results showed that, compared to source and destination populations, the gut microbiome of the migrating population was closer to the destination population (p < 0.01). However, the abundance of Ruminococcus f_Luminocccae and seven other microorganisms remained similar to the African population. Also, the migrating population had unique Gemmiger and Catenibacteria microbial communities. Further research indicated that environmental factors affecting population microbial composition included time spent in China, coffee intake, and sleep rhythm. Finally, constructing a random forest model for microbial differences among the three populations achieved 81.9 % accuracy in population inference. This study can identify migratory groups and confirm individuals' place of residence and ethnic origin, offering assistance for forensic individual tracing.