Fig. 4.

Abundance and expression pattern of genes involved in amino acid metabolism in gut microbiotas of different host species. Bray–Curtis distance between groups calculated with gene families encoding amino acid metabolic enzyme based on gene abundance from metagenomic (A AA degradation, C AA biosynthesis) and expression from meta-transcriptomic data (B AA degradation, D AA biosynthesis). The ellipses were calculated and drawn with a 0.95 confidence level