Research On Neutral Theory Of Human Microbial Community

Background:A central goal of community ecology is to understand the forces that maintain species diversity within communities. Niche theory and neutral theory are main theory for explaining mechanism of maintain species diversity. But niche theory can not supply enough niches to contain so many diversity in microbial community, so neutral theory maybe more appropriate. So far, neutral theory rarely tested in microbial community, especially in human microbial community.16s rRNA sequencing has become the main method for researching microbial community as the development of sequencing technology. Also, human microbial community are closely related with heath, disease and medicines. The "human microbial project" (HMP) initiated by National Institutes of Health (NIH) and MetaHIT project financed by the European Commission have collected mass human microbial samples? In this research, we use the HMP data to present a comprehensive test of the neutral theory with human microbiome data.Methods(1) Using neutral model test Species rank abundance.(2) Using neutral model from master equation test species abundance distribution.(3) Fitting neutral model in sites, locations and individuals level.(4) Using Ewens sampling formula for testing neutral theory(5) Using Etienne sampling formula for testing neutral theory.(6) Testing dispersal-limited by distance-decay model.Results:(1) About half samples of Right Antecubital fossa and Left Antecubital fossa satisfied the neutral model according to the species rank abundance and species abundance distribution. While samples from the Mid vagina, Posterior fornix and Vaginal introitus can not fit to neutral model.(2) Neutral model from master equation can predict median abundance species very well, but this model can not explain the coexist mechanism of dominance species and rare species.(3) When combined the microbial community of different sites in the same location or individual, Combined community can not fits neutral model.(4) Compared the result of Ewens sampling formula and Etienne sampling formula,. Both formulae made no differences in almost all human microbial communities we tested. This result according to distance-decay model show that there are no dispersal-limited in human microbial communities.