Heritability of Christensenellaceae and Methanogens and their role in metabolism

A gut microbial consortium that impacts adiposity - Our search in twins for specific gut microbes responsive to host genotype identified the bacterial family Christensenellaceae as the most highly heritable taxon. Its high heritability has since been confirmed in three independent populations, including one in Korea. This family forms the hub of a co-occurrence network that includes methanogenic Archaea, namely Methanobrevibacter smithii. We noted that this consortium was enriched in lean versus obese subjects. Indeed, the Christensenellaceae-methanogen consortium is consistently associated with a healthy metabolic status in the host across populations. Using gnotobiotics, we have demonstrated that the introduction of Christensenella minuta, into an obese-microbiome protects against its obesogenic effects in germfree mice. Project Leader Jill Waters is leading the effort to dissect the molecular underpinnings of this effect and to better understand the host phenotype.

Genomics of archaeal heritability - Our heritable-microbe screen also revealed methanogenic Archaea. The methanogens of the human gut are thought to influence fermentation dynamics by uptake of H2 and CO2, and also possibly trimethylamine production through the use of methyl groups. Project Leader Nick Youngblut is leading efforts to characterize the genomic basis for heritability in the human gut methanogens and is taking a comparative phylogenetic approach to letter understand the mammalian-archaeal relationship.