To shed light on the natural history of Precambrian life, the evolutionary history of almost 4,000 gene families across the three domains of life are mapped onto a geological timeline. Over one-quarter of modern gene families arose during a period of rapid diversification of bacterial lineages. Functionally, these genes are likely to be involved in electron transport and respiratory pathways, whereas those that arose later are implicated in functions consistent with an increasingly oxygenating biosphere.
- Lawrence A. David
- Eric J. Alm