Types and characteristics of shared microbiota within families of ethnic minorities in Inner Mongolia.

Cohabitation within the same family was the most significant determinant of gut microbial variation at both macrodiversity and microdiversity levels.

• The study characterized gut microbial composition of 25 ethnic minority families from Inner Mongolia.
• Family cohabitation was more significant than other factors including family role, ethnicity, sex, age, and geographical region.
• Both macrodiversity (community composition) and microdiversity (genetic heterogeneity within species) were analyzed.

Seventeen bacterial strains were identified as shared within families based on average nucleotide identity.

• Average nucleotide identity (ANI) was the method used to identify shared strains.
• Bifidobacterium adolescentis and Holdemanella biformis demonstrated higher average abundance among the shared strains.
• Eubacterium rectale and Clostridiales bacterium were shared more frequently and across multiple families.
• A total of 17 distinct bacterial strains were identified as being shared within families.

Most shared strains possess the genetic potential for production or biosynthesis of short-chain fatty acids (SCFAs).

• Annotation was performed against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database.
• The SCFA biosynthetic potential was identified across the majority of the 17 shared strains.
• This finding suggests a potential metabolic role for the shared family microbiota in SCFA production.

Shared bacterial strains showed relatively low non-synonymous to synonymous polymorphism (pN/pS) ratios.

• Computational analysis was used to assess pN/pS ratios in genes of shared strains.
• Low pN/pS ratios indicate relatively strong purifying selection acting on these shared strains.
• This analysis was conducted at the microdiversity level, examining genetic heterogeneity within species.

With the exception of Clostridiales bacterium, shared strains generally did not occupy central nodes within the microbial interaction network.

• Correlation network analysis was used to assess the position of shared strains within the gut microbial ecosystem.
• Clostridiales bacterium was the sole shared strain identified as occupying a central node in the network.
• The peripheral network position of most shared strains suggests they are not dominant hubs in microbial interactions.

The study populations included ethnic minorities from Inner Mongolia—Daur, Evenki, and Buryat—who consume a diet high in fat, protein, and low in fiber.

• The Seventh National Population Census reported Daur, Evenki, and Buryat populations at 132,299, 34,617, and 436,000, respectively.
• These minority groups primarily consume dairy products and meat.
• Their dietary pattern may elevate risks of obesity, diabetes, and cardiovascular diseases.
• 25 ethnic minority families participated in the study.