Universal scaling across biochemical networks on Earth

• Published in: Science advances Vol. 5; no. 1; p. eaau0149
• Main Authors: Kim, Hyunju, Smith, Harrison B, Mathis, Cole, Raymond, Jason, Walker, Sara I
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.01.2019
• Subjects: Archaea - chemistry; Archaea - genetics; Bacteria - chemistry; Bacteria - genetics; Biochemical Phenomena; Biological Evolution; Catalysis; Cluster Analysis; Computational Biology - methods; Earth, Planet; Ecosystem; Enzymes - chemistry; Enzymes - genetics; Enzymes - metabolism; Genome; Metabolic Networks and Pathways; Metagenome; Random Allocation; SciAdv r-articles; Systems Biology
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aau0149

The application of network science to biology has advanced our understanding of the metabolism of individual organisms and the organization of ecosystems but has scarcely been applied to life at a planetary scale. To characterize planetary-scale biochemistry, we constructed biochemical networks using a global database of 28,146 annotated genomes and metagenomes and 8658 cataloged biochemical reactions. We uncover scaling laws governing biochemical diversity and network structure shared across levels of organization from individuals to ecosystems, to the biosphere as a whole. Comparing real biochemical reaction networks to random reaction networks reveals that the observed biological scaling is not a product of chemistry alone but instead emerges due to the particular structure of selected reactions commonly participating in living processes. We show that the topology of biochemical networks for the three domains of life is quantitatively distinguishable, with >80% accuracy in predicting evolutionary domain based on biochemical network size and average topology. Together, our results point to a deeper level of organization in biochemical networks than what has been understood so far.