Diversity of cyanobacterial biomarker genes from the stromatolites of Shark Bay, Western Australia

Research at Shark Bay's stromatolites reveals that cyanobacteria, not non-cyanobacterial species, dominate the production of 2-methylhopanoids—a key biomarker for tracing evolutionary history. This challenges previous assumptions by demonstrating that 11 out of 12 operational taxonomic units (OTUs) identified in microbial mats are cyanobacteria, based on phylogenetic analysis of the hpnP gene. The study analyzed genomic DNA from pustular and smooth microbial mats to construct an hpnP clone library, sequencing 117 partial clones. These findings clarify that cyanobacteria, not other bacteria, are the primary producers of this biomarker in Shark Bay's stromatolites, offering new insights into ancient microbial ecosystems.

Garby, T. J., Walter, M. R., Larkum, A. W. D., & Neilan, B. A. (2012). Diversity of cyanobacterial biomarker genes from the stromatolites of Shark Bay, Western Australia. Environmental Microbiology, 15(5), 1464–1475. Portico. https://doi.org/10.1111/j.1462-2920.2012.02809.x