Prediction of BMI traits in the Chinese population based on the gut metagenome

Background: Identifying the individual characteristics of trace evidence left at a crime scene is crucial in forensic identification. Microbial communities found in fecal traces have high individual specificity and could serve as potential markers for forensic characterization. Previous research has established that predicting body type based on the relative abundance of gut microbiome is relatively accurate. However, the long-term stability and high individual specificity of gut microbiome are closely linked to changes in the microbiome genome levels. No studies have been conducted to deduce body size from genetic traits. Therefore, this study investigates the vital role of gut bacterial community characteristics and genetic traits in predicting body mass index (BMI) using gut metagenomic data from a healthy Chinese population. Results: : Regarding the gut microbial community, the underweight group displayed increased α-diversity in comparison to the other BMI groups. There were significant variations in the relative abundance of 19 species between these three BMI groups. There were significant differences in the relative abundance of 19 species among these three BMI groups. The BMI prediction model, based on the 31 most significant species, showed a goodness of fit (R 2 ) of 0.56 and a mean absolute error (MAE) of 2.09 kg/m 2 . The overweight group exhibited significantly higher α-diversity than the other BMI groups at the level of gut microbial genes. Furthermore, there were significant variations observed in the single-nucleotide polymorphisms (SNP) density of 732 contigs between these three BMI groups. The BMI prediction model, reliant on the 62 most contributing contigs, exhibited a model R 2 of 0.72 and a MAE of 1.56 kg/m 2 . The model predicting body type from 44 contigs correctly identified 93.55% of the study participants. Conclusion: Based on metagenomic data from a healthy Chinese population, we demonstrate the potential of genetic traits of gut bacteria to predict an individual's BMI. This discovery suggests a novel method for determining the body type of suspects in forensic applications using the genetic traits of the gut microbiome and holds great promise for forensic individual identification. This work was supported by National Natural Science Foundation of China Youth Science Fund Project (81701865), Hebei Province Natural Science Foundation Project (H2020206107).