The Great Oxidation Event can be detected and dated through the genetic record

Traditionally, the biogeochemical information preserved in the rock record has been used to study the environmental conditions of Earth’s past. There is however another important record of Earth’s history that is only just beginning to be explored: the genomes of contemporary organisms (i.e. the genetic record). The genetic record is an under-utilized tool for studying Earth History. Like the rock record, the genomes of microorganisms have been imprinted with information regarding our changing planet. In this presentation, we will describe a framework for accessing and interpreting the “genetic scars” imprinted on the genomes of microorganisms to identify the timing of the Great Oxidation Event (GOE) independent of the geochemical record. This approach combines ideas from systems biology and data science to infer the timing of major changes in the evolution of microbial lineages and metabolic pathways. Briefly, a horizontal gene transfer constrained molecular clock provides timeline for major speciation events within the bacterial tree of life which can be used to date the emergence of specific protein families related to oxygenic photosynthesis and oxygen consumption. A feature selection algorithm for metabolic networks allows us to generalise this technique beyond the GOE and will enable us to better interpret isotope anomalies in the geochemical record.