These authors contributed equally to this work.
Horizontal gene transfer and the rock record: comparative genomics of phylogenetically distant bacteria that induce wrinkle structure formation in modern sediments
Article first published online: 2 JAN 2014
© 2014 John Wiley & Sons Ltd
Volume 12, Issue 2, pages 119–132, March 2014
How to Cite
Flood, B. E., Bailey, J. V. and Biddle, J. F. (2014), Horizontal gene transfer and the rock record: comparative genomics of phylogenetically distant bacteria that induce wrinkle structure formation in modern sediments. Geobiology, 12: 119–132. doi: 10.1111/gbi.12072
- Issue published online: 12 FEB 2014
- Article first published online: 2 JAN 2014
- Manuscript Accepted: 27 NOV 2013
- Manuscript Received: 3 MAR 2013
Wrinkle structures are sedimentary features that are produced primarily through the trapping and binding of siliciclastic sediments by mat-forming micro-organisms. Wrinkle structures and related sedimentary structures in the rock record are commonly interpreted to represent the stabilizing influence of cyanobacteria on sediments because cyanobacteria are known to produce similar textures and structures in modern tidal flat settings. However, other extant bacteria such as filamentous representatives of the family Beggiatoaceae can also interact with sediments to produce sedimentary features that morphologically resemble many of those associated with cyanobacteria-dominated mats. While Beggiatoa spp. and cyanobacteria are metabolically and phylogenetically distant, genomic analyses show that the two groups share hundreds of homologous genes, likely as the result of horizontal gene transfer. The comparative genomics results described here suggest that some horizontally transferred genes may code for phenotypic traits such as filament formation, chemotaxis, and the production of extracellular polymeric substances that potentially underlie the similar biostabilizing influences of these organisms on sediments. We suggest that the ecological utility of certain basic life modes such as the construction of mats and biofilms, coupled with the lateral mobility of genes in the microbial world, introduces an element of uncertainty into the inference of specific phylogenetic origins from gross morphological features preserved in the ancient rock record.